The Source node menu contains the nodes used to create and import imagery. The Image In node is used to import digital image data from disk for modification. Other source nodes are used to create new elements, such as color fields and gradients.
The Source menu also includes the Image Out node, which is used to specify that the image data flowing into it will be rendered to disk.
The source nodes in RAYZ provide a set of parameters used to specify basic attributes of the output frame:
Fig. 14.1 Frame Attribute Parameters.
The exception is the Image In node, which imports existing image files from disk rather than creating images from scratch. The following descriptions of the individual frame attribute parameters will note if there are any differences in a parameter among the nodes.
This parameter enables you to specify the width and height of the frame that will be output by a source node.
You can key a pair of values into the Width and Height fields, or you can use the associated menu to access a list of commonly used film and video resolutions. When you select a resolution from the list, the corresponding XY values are entered into the parameter fields.
Fig. 14.2 Drag a scroll bar up to increase field value; drag down to decrease. To change the value in finer increments, drag the scroll bar to the left or right--the value will change more gradually.
Use any of the following methods to adjust the size parameters:
The Color Bars node does not include a Size parameter, as the output size is limited to the resolution associated with the specified video type (NTSC or PAL).
In the Image In node, the Size parameter specifies the resolution of the full size imagery when proxies are used in lieu of full size images, rather than in conjunction with them, as explained in Specifying Full Size in the Image In node description. (To change the resolution of imported imagery, connect the Image In node to an appropriate node such as Resize.)
The Bit Depth menu enables you to select 8-bit, 16-bit, or floating point ("32-bit") per channel as the bit depth of the output.
In the Image In node, you can convert the bit depth of imported images by using the Conversion Parameters.
The Channels menu enables you to select the number and type of image channels to output: RGB, RGBA, or Alpha only. The alpha, or matte, channel contains the data that determines the transparency level of the RGB elements of each pixel.
In the Image In node, you can add an alpha channel to imported imagery by checking the Alpha parameter, or you can connect the Image In node to a Channel Swap Node in chapter 16 to make other adjustments.
The source nodes include parameters in which you can specify the frame number to start at and the total length of the sequence. The default values are set to match the current range specified in the Time Scooter. To adjust the range, simply type new values into the Start At and Length fields.
Use the Clip Editor to do more complex re-sequencing, such as looping an animated ramp in a Gradient node. |
The frame range parameters in the Image In node can be expanded to specify which frames in the sequence to import, as explained in the section of the Image In node description on Frame Range to Import.
The Backing Color parameter value only becomes relevant in the event that an image is scaled or otherwise transformed such that some areas within the full size frame border no longer contain image data. For example, if you scale down an image in a Transform node, RAYZ will fill the empty pixels inside the frame border with the designated backing color.
Fig. 14.3 The backing color becomes relevant when an image (left) is scaled down (right) or transformed in any other way that leaves part of the frame "empty."
By default the backing color is black (0) for all channels, and in most cases this is appropriate. In fact, you may never need to adjust the default value. If you wish to assign another color to the backing area, however, you can do so in the source node. The backing color assigned in the source node is used throughout the node network.
The Backing Color parameter controls work exactly like those described in the section on Using the Color Parameters in the Color node description.
The Backing Color parameters for the Image In node are located within the Image Description Parameters.
The Checker node creates a checkerboard pattern in the colors and dimensions you specify.
You can specify frame size, bit depth, channels, and range of the output as described in the section on Frame Attribute Parameters Common to Source Nodes.
The other parameters in the Checker Node Panel, which are described below, are used to set the size of the squares that make up the checkerboard (the Square Size parameter) and the two colors that distinguish the alternating pattern of squares (Square Color and Background Color).
The Square Color and Background Color parameters use the standard RAYZ color controls, which are described in the section on Using the Color Parameters.
Use the Square Color parameter controls to specify the color of the squares. The square color is set to white by default, including the Alpha channel, assuming you have specified RGBA output in the Channels menu.
Use the Background Color parameter controls to specify the color of the background squares. The background color is set to black by default, including the Alpha channel, assuming you have specified RGBA output in the Channels menu.
If you want the entire checkerboard pattern to be opaque, remember to set the Alpha channel value in the Background Color parameters to maximum value.
Use the X and Y fields of the Square Size parameter to specify the size, in pixels, of the squares that make up the checkerboard pattern. The default size is 64 x 64.
The squares do not actually have to be square; if you enter a different size in each field, you will create a pattern of rectangles.
The Circle Ramp node creates a circular gradient in the color and dimensions you specify. For example, you could use the Circle Ramp node to create a vignette mask by defining a circle with graduated opacity from center to edge and applying it to the alpha channel only.
You can use the Circle Ramp overlay in the Image Viewer to adjust the position and radius interactively and the corresponding parameter values in the Node Panel will update accordingly.
Fig. 14.4 Circle Ramp Overlay: Drag the overlay controls in the Image Viewer to adjust the ramp characteristics.
You can specify frame size, bit depth, channels, and range, as described in the section on Frame Attribute Parameters Common to Source Nodes. The other Circle Ramp parameters are described next.
The Center Color and Edge Color parameters are used to set the color values of the center and edge of the radius. The values in between are interpolated linearly.
Both parameter groups feature identical color controls which are standard to RAYZ. If you need more information, these controls are described in detail in the section on Using the Color Parameters in the Color node description.
This parameter is used to position the circle in the frame. The center of the circle is positioned at the x,y coordinates entered into the Center parameter fields. The coordinate values are expressed as a percentage of the total width and height of the output frame, so that the default values of 0.5 for both fields will center the circle in the frame.
The Center parameter is not bounded--you can set values outside the range of 0 to 1 to center the circle outside of the frame.
This parameter sets the size of the circle by specifying its radius. A pair of fields are used that represent the inner (I) and outer (O) limits of the radius, expressed as a percentage of the width of the output frame. The outgoing radius is not bounded; it can be set to values greater than 1.
This parameter controls the aspect ratio of the circle, which can be adjusted from a true circle to an ellipse. To flatten the circle into a horizontal ellipse, decrease the Aspect value from its default of 1; to create a vertical ellipse, increase the value.
The Color node enables you to create a solid field of color using the values you specify in the Node Panel.
The output of the Color node will be RGB(A) color channels, but you can choose the model in which to specify the color: RGB, HSV, or Constant Luminance. You can also control the value of the alpha channel output, if any.
The Color Node Panel consists of the Color parameter group and the Frame Attribute parameters. The frame parameters, including size, bit-depth, channels, range, and backing color, are described in Frame Attribute Parameters Common to Source Nodes. The color parameters are described next.
The Color parameter group in the Color Node Panel is also available in other nodes in which you might need to specify color values:
Fig. 14.5 Color parameter group expanded, with the RGB tools selected. Note the colorspace selector buttons, which are used to display the RGB, HSV, or Constant Luminance controls.
The Color Picker tools located in the top row can be used to select a color from a popup spectrum bar, to sample a color in an image, or to pick a color stored in any other color swatch in RAYZ.
There is also an animation menu that can be used to animate the color values over time, as described in Animation Menu Options in chapter 7.
The Color Swatch shows the currently specified color (the default is white; that is, the maximum value for the specified bit depth, such as 255 for 8-bit color).
You can also use the swatch to specify a new color: right-hold on the swatch to access a popup color spectrum, drag across the spectrum to the color you want use, and release the mouse button.
Fig. 14.6 One way to specify a color is to select it from the popup spectrum strip accessed by right-holding on the Color Swatch.
Use the eyedropper tool to fill the Color node with the value of a specific image pixel or of another RAYZ color swatch. Color swatches are available in any other node that uses color parameters and in the Image Viewer's Color Picker.
The eyedropper tool samples both the RGB values and the alpha channel value, if any.
Click the eyedropper tool and the cursor will change to an eyedropper icon. Move the eyedropper cursor over the pixel you want to pick and click, scrub or drag a bounding box, depending on the sample method selected from the associated menu.
Fig. 14.7 Options available in the Sample Method menu. The option selected determines how image pixels are sampled and whether to use the average, minimum, or maximum value of the sampled pixels.
Use this menu to select the sample method to use when picking pixels in an image. The default method lets you click an individual pixel or scrub across an area of pixels and gives you the average value of the sampled pixels. However, you can also choose Scrub/Min or Scrub/Max to get the minimum or maximum value of the sampled pixels.
The other method lets you drag a bounding box around the pixels to be sampled. As with the scrub method, you can select whether to use the average, minimum, or maximum value of the sampled area.
Select the colorspace model you want to use to specify the color values: RGB, HSV, or Constant Luminance. The interactive display and corresponding numeric fields are linked--changing one updates the other accordingly. The interactive display is dynamic; that is, the nature of the display changes to represent the selected color model.
This is the default colorspace setting, as shown in Fig. 14.5. You can enter specific RGB values into the fields, or you can use the interactive display to select a color.
In the interactive display, start by dragging the vertical color slider to select a color from the strip. The range for that color will appear in the box to the left of it. Then click a specific point in the range.
The RGB parameters are set in a range of 0-max, where max represents the highest value at the selected bit depth (0-65535 in 16-bit, e.g.). The range updates automatically to reflect the current selection in the Bit Depth menu.
Select HSV to display a hue-based color model. Use the color wheel to select a specific hue at a specific saturation. The closer to the center, the higher the saturation. Drag the vertical slider to the right of the color wheel to adjust the Value parameter.
The Hue parameter range is from 0 to 360, representing a color wheel. The Saturation and Value parameters are set in a range of 0-1. (For more information about working in HSV space, refer to the description of the Hue Adjust Node in chapter 16).
Select this option when you need to restrict the color selection range to a specific luminance value.
Use the vertical slider in the center to select the luminance level, and the available color range at that luminance will update accordingly. Then select a color from the range by clicking on it.
Fig. 14.9 Constant Luminance color tools.
The Color Bars node generates a test pattern of color bars for broadcast applications.
Like other source nodes in RAYZ, the Color Bars node also provides parameters to set the bit depth, channels, frame range, and backing color of the output. Refer to Frame Attribute Parameters Common to Source Nodes if you need more information about setting these parameters.
Channel selection in the Color Bars node is limited to RGB or RGBA output. And unlike the other source nodes, the size is limited to the choices in the Standard menu, which is described below. |
The size of the output frame is limited to the size of the CCIR broadcast standard you choose in the Standard menu:
The Intensity menu enables you to change the intensity from the default level of 75 percent to 100 percent.
The File Group node is used to import a RAYZ file that has been configured as a customized group. This way, a particular procedure or effect can be distributed to multiple compositors with consistent results. In addition, if any changes are made to the master group file, all File Group nodes pointing to that file can be updated to match the latest version.
The File Group node has no inputs or outputs when it is created. Once a RAYZ file has been imported into the node, it will have as many inputs and outputs as were specified in the imported file.
When a new File Group node is created, the only parameters in the Node Panel are Edit Group Inputs/Outputs, Reload Project, and File.
Once you use the File parameter to load a RAYZ project file, however, the Node Panel will contain any parameters that have been exported to it, which may be from any node in the file.
The File parameter must be specified before you do anything else--the node is just an empty shell until you do. You can type the full pathname of the project file you want to access into the File field, or you can click the file folder button to bring up a dialog box in which you can navigate your directory structure to locate the file.
Click this button whenever a change has been made to the master file referenced by the File parameter to force RAYZ to update the contents of the File Group node.
The Gradient node enables you to create a color gradient using the values you specify. Most commonly, the Gradient node is used to create matte or mask data with smoothly graduated changes in alpha values.
The Gradient Node Panel provides controls for creating the gradient and for specifying the output frame attributes, including size, bit depth, channels, frame range, and backing color. The frame parameters are described in Frame Attribute Parameters Common to Source Nodes. The parameters specific to creating a gradient are described next.
To create a circular gradient, use the Circle Ramp Node. |
By default, the Gradient node creates a grayscale linear ramp from transparent to opaque. However, you can adjust the direction and length of the gradient vector by using the interactive vector line in the Image Viewer or by entering specific x,y coordinates into the Line Start and Line End parameters in the Node Panel. These controls are interdependent; when you change the line position in the Image Viewer, the parameters in the Node Panel update automatically, and vice versa.
Fig. 14.10 The Gradient overlay in the Image Viewer is shown on top; below it are the corresponding parameters in the Gradient Node Panel.
You can also use the controls in the Gradient Node Panel to adjust the opacity and color of the ramp, and you can add adjustment points to further manipulate the color frequency distribution.
To add points and adjust their color and opacity, use the Ramp Editor in the Node Panel. To add a point, select a color from the Spectrum strip (located directly below the Ramp Editor) and drag it into the Ramp Editor at the desired location along the ramp. When you release the mouse button over the ramp, a new point is created, which is indicated by a triangle pointer at the bottom of the Ramp Editor display.
Fig. 14.11 The top image shows how to use the spectrum strip to create a new point in the Ramp Editor; the bottom image shows how to adjust a point.
You can adjust the position, color, and opacity of the currently selected point. Click the triangle pointer for any point to select it:
The Grid node creates a grid pattern in the colors and dimensions you specify.
You can specify frame size, bit depth, channels, and range of the output as described in the section on Frame Attribute Parameters Common to Source Nodes.
The other parameters in the Grid Node Panel, which are described below, are used to set the width and spacing of the grid (Line Width and Line Gap), as well as the color of the grid lines and the background (Line Color and Background Color).
The Line Color and Background Color parameters use the standard RAYZ color controls, which are described in the section on Using the Color Parameters.
Use the Line Color parameter controls to specify the color of the grid lines. The line color is set to white by default, including the Alpha channel, assuming you have specified RGBA output in the Channels menu.
Use the Background Color parameter controls to specify the color of the background behind the grid lines. The background color is set to black by default, including the Alpha channel, assuming you have specified RGBA output in the Channels menu.
If you want the entire grid pattern to be opaque, remember to set the Alpha channel value in the Background Color parameters to maximum value.
Use the Line Width parameter to specify the width of the grid lines, in pixels. The default line width is 5 pixels.
Use the Line Gap parameter to specify the size of the gap between grid lines, in pixels. The default gap size if 50 pixels.
The Image In node enables you to load an image sequence from your local hard disk or from a remote directory on a shared volume. Most RAYZ networks begin with one or more Image In nodes.
The Import Footage (Ctrl-i) command is a great shortcut for importing images. It opens the same file chooser that you access from the Image In Node Panel, and when you select a sequence it creates the Image In node for you automatically with that sequence specified in the File parameter. You can select as many sequences, and create as many new Image In nodes as you want, all without ever closing the dialog. For more information, refer to Chapter 10: Importing Images. |
You specify the image sequence to import by using either of the following methods:
Once the imagery has been loaded into RAYZ, you can adjust various parameters in the Image In Node Panel if necessary. As explained in the following sections of this node description, you can
You can import virtually any image format into RAYZ. For a complete list, see Appendix B: Image File Formats Supported by RAYZ.
For some image formats you may want to take advantage of certain conversion options when the files are imported. RAYZ automatically provides the parameters for such options when the relevant file type is imported.
You can convert the bit depth and distribution type (nonlinear to linear) of the image data, as described in Conversion Parameters.
RAYZ automatically converts Cineon log files to 16-bit linear. However, you can change this conversion using the appropriate parameters in the Conversion group. |
You can also specify the true pixel ratio for "squeezed" anamorphic imagery, and override the default setting for premultiplication, as described in the section on the Image Description Parameters.
A single Image In node is used to specify both the full size version of an image sequence and any proxy files that are available for that sequence.
If proxy files have been specified in the Image In node, RAYZ will use them whenever Medium or Low resolution is selected from the Size menu in the Image Viewer. If proxies have not been specified, RAYZ will scale down the full size imagery and send the scaled-down image data through the network. The parameters used to specify proxies are described in the section on Proxy Parameters.
The Image In node parameters described in this section are used to specify full size and proxy images to import, to re-sequence frames, and to add an alpha channel. However, the node also offers parameters to control conversion, specify certain image characteristics, and set format-specific options when applicable. These parameters are described in the sections on Conversion Parameters, Image Description Parameters, and Format-Specific Import Options.
Fig. 14.12 Image In parameters in the Node Panel.
The Full parameter group is used to specify the full size imagery to be loaded into the node and includes the File, Format, and Flip parameters.
This parameter specifies the location of the image files to be imported. You can type the complete pathname into the field, or you can click the folder button associated with the Full Path field to access a File dialog box.
The File dialog enables you to navigate through directory hierarchies and examine lists of files to find a file or sequence to import. Once you locate it, click on its name in the file list to select it and then click the Accept button. (Alternatively, you can double-click on its name in the file list.) The dialog box will close and the selected images will be loaded into RAYZ.
The File field and the other Image In Node Panel parameters will update with information specific to the imagery that has been loaded.
You may never need to use this menu. The Format menu lists the file formats that can be imported by RAYZ. The default choice is "Automatic," which indicates that RAYZ will examine the image files to determine their format. If it cannot determine the file type for any reason, an error message will appear. In such a case, use the Format menu to tell RAYZ the file type of the image you are attempting to import.
Certain file formats invert the orientation of images. Click the Flip checkbox to flip the imagery vertically. (This box can be checked or unchecked at any time to change the orientation of the image.)
The Full Size parameter is grayed out (unavailable) unless you import proxy images without specifying a full size image source. For more information, refer to the Proxy Parameters section of this node description.
Check this box to add an alpha channel to the imagery. The alpha is a uniform field set to full opacity (white). To create an alpha using any other criteria, connect the Image In node to an appropriate node, such as Channel Swap, Chromakey, Roto, or an Ultimatte node.
The frame range parameters in the Image In Node Panel are used to specify the frame number in RAYZ at which the sequence should start and to specify the range of frames to import. They are set by default to values that represent the sequence being imported, however, they can be changed by typing new values in the fields.
Fig. 14.13 You can expand the frame range group to access the Source Begin and End parameters.
The Start At parameter is used to specify at which frame number in the shot the imported sequence should start (the default is frame 1). The Length parameter specifies the total number of frames.
You can expand the parameter group to access the Source Begin and End parameters, which are used to import a subset of the total frame range available on disk.
The fields are interdependent; for example, if you change the End value the Length value will update accordingly.
The frame range parameters in Image In are the fastest way to make several of the most common adjustments to a sequence, such as changing the start-frame number. To do more extensive re-sequencing, however, use the Clip Editor, which displays each clip as a film strip in an interactive timeline. This is especially useful when you want to
The Clip Editor settings override the parameter settings in the Node Panel. This means that once you edit a sequence in the Clip Editor, the frame range parameters in the Node Panel are deactivated. |
For more information, see Using the Clip Editor in chapter 12.
The Medium and Low proxy parameters are used only when you want to specify lower resolution files to use in place of the full resolution imagery. You can specify Medium proxies, Low proxies, or both.
The Medium and Low parameter groups can be expanded to reveal the same set of parameters available for the full size input. These parameters work exactly the same way to specify the file path and flip the input, as described previously in the section on the Full Parameter Group.
The Add Alpha and frame range parameters in the Image In Node Panel apply to all imagery specified in the node, proxies and full size. |
You can import proxy files and start building a shot even when the full size imagery is not yet available. All you need do is specify what resolution the full size imagery will be in the Full Size parameter, which becomes active whenever you use the proxy parameters to import imagery without first specifying an image sequence in the Full parameter group.
You can type width and height values into the entry fields or use the menu to select a resolution from the list.
Fig. 14.14 This example shows 2K proxy files imported into the Medium File parameter and the Full Size parameter set to 4K resolution. Note that full size image files have not actually been specified.
The Conversion parameters enable you to perform linear-to-linear conversions using the Bit Depth menu or nonlinear-to-linear conversions using the Type and Bit Depth menus. Based on the current selection in the Type menu, additional parameters may become active.
Fig. 14.15 Expand the Conversion group to access the specific parameters relevant to the imported image format.
The parameters in the Conversion group default to neutral settings, which do not convert the imagery, with the exception of Cineon 10-bit log files, as explained next.
By default, Cineon log files (Fido or DPX) are converted to 16-bit linear colorspace. However, you can opt instead to convert the imagery to floating point or 8-bit linear (using the Bit Depth menu).
You also have the option not to convert the log data at all (by selecting None from the Type menu), as when you want to perform color corrections in log space. You can always convert the color corrected log image to linear later by using a Log To Lin Node in chapter 20 downstream in the node network.
By default, log image data is displayed in the Image Viewer using Raw Log display conversion. If you prefer Cineview emulation, select it in the Viewer's Display Conversion in chapter 6 parameters. |
When converting a Cineon image from log to linear, you can also adjust the default settings used to remap the color values. The easiest way is probably to change the Maximum Log parameter value, which automatically changes the relevant log conversion parameters accordingly. For even more control, however, you can expand the Advanced Cineon Parameters group and adjust any of the individual log conversion parameters.
You can convert imagery to 8-bit, 16-bit, or floating point precision per channel by selecting a bit depth from the menu. For linear image data, the Bit Depth menu defaults to the native resolution of the imported files.
The Type menu is used to convert nonlinear data distributions to linear:
With the exception of Cineon Fido and YUV files, the Type menu defaults to None (no conversion). Cineon files default to "From Log" and YUV files default to "From Video."
This parameter becomes active when From Video is selected in the Type menu. It is used to specify that a nonlinear gamma correction has been applied to the imagery being imported. RAYZ will then convert the color channels of the image from the specified gamma to linear gamma (1.0). The Alpha channel, if there is one, is not affected.
Fig. 14.16 The Video Gamma parameter defaults to 2.2, to match the gamma value commonly encoded in YUV imagery.
This parameter becomes active when From Log is selected in the Type menu. RAYZ uses the Maximum Log value to compute the linear white value used in the conversion. (Conversely, if you modify the log parameters in the Advanced group, the Maximum Log parameter is updated accordingly.)
Fig. 14.17 When From Log is selected from the Type menu, the Maximum Log parameter and the Advanced parameters become active.
The default value for Maximum Log is 685, however you can change it to reflect the actual maximum value in the image being converted. If the highlights in the image seem "blown out," for example, raise the Maximum Log value until they look right.
When you raise the Maximum Log value, RAYZ recalculates the optimal Linear 90% White value, lowering it from its default of 65535 to create headroom in linear space to accommodate specular highlights and other extremely bright image data captured in the original photography.
Be aware, however, that the lower the Linear White value, the smaller the range becomes into which the majority of the image data is remapped. Another option is to convert the log data to linear float, which will not clip the highs.
The Advanced parameter group provides complete control over the Cineon log conversion process. The Advanced parameters become available when From Log is selected in the Conversion Type menu.
Fig. 14.18 Expand the Advanced parameter group to access the full set of Cineon log conversion variables.
By default, Image In remaps Cineon log files to 16-bit linear by stretching the log data in a constant slope to fill the 16-bit space, using standard values of 685 for log 90% white and 65535 for linear 90% white.
The default values for Cineon conversion are based on specifications published by Kodak Motion Picture & Television Imaging and Cinesite Digital Film Center in "Grayscale Transformations" (1993) and "Conversion of 10-bit Log Film Data to 8-bit Linear or Video Data" (1995). These documents can be downloaded in Acrobat PDF format, which is suitable for printing, from Silicon Grail at ftp://ftp.sgrail.com/pub/reference/cineon. They are also posted on the Technical Documents page of the Cinesite Hollywood website at http://www.cinesite.com/la/scanrec/techdocs.html. |
Depending on the nature of the specific Cineon files you are importing, you may want to adjust the Advanced parameters:
Reference Black: This parameter specifies the value used for reference black in the conversion operation. The default value is 95, which represents Dmin (the minimum printing density, or blackest black that can be recorded, about equivalent to the 1% black card).
Log 90% White: This parameter specifies the value used for log 90% white in the conversion operation. The default is 685, which represents the code value of the 90% white card for a normally exposed film negative.
Linear 90% White: This parameter specifies the value in linear space to which the log 90% white value will be mapped in the conversion operation. The default is 65535 (in 16-bit), which will clip any values above 685 in the original log file. When converting to linear float, however, values are not clipped at 1.
Display Gamma: This parameter specifies the value used for display gamma in the conversion operation. The default value is 1.7.
Film Gamma: This parameter specifies the value used for film gamma in the conversion operation. The default value is 0.6.
Softclip: Softclip can be used, if necessary, to reduce the effects of harsh clamping at the high end when remapping log data. Check the Softclip box to enable this option and set a positive softclip value in the associated parameter field.
The Softclip parameter can be adjusted in the range of 0-100. This value is subtracted from the Log 90% White value to create a breakpoint below peak white. The slope of the distribution curve above the breakpoint becomes nonlinear to remap the highs more gradually.
This parameter group is used to specify various characteristics of the imagery being imported, including the premultiplication status, pixel ratio, and backing color of the imagery. RAYZ can then use this information in other nodes to adjust default parameters or Image Viewer display settings.
Fig. 14.19 Expand the Image Description group to access parameters that identify whether an RGBA image is premultiplied as well as whether an image has a non-square pixel ratio.
The Is Premultiplied checkbox tells RAYZ whether or not the imagery has been premultiplied. RAYZ sets this parameter automatically based on the number of channels in the image being imported: an RGBA image is assumed to be premultiplied and an RGB image, unpremultiplied. You can use this checkbox to override the setting if necessary for a particular image.
The premultiplication status of an image is important when an image is composited, because premultiplying the RGB channels of an input by the alpha channel is an initial step in many compositing operations. See About Premultiplication in chapter 18 for more information.
This parameter specifies the pixel ratio of the imagery. The pixel ratio (as distinct from the aspect ratio) refers to the ratio between the number of pixels used vertically and horizontally, per equal unit of measure, to encode the image data.
Most digital imagery has a square pixel spacing ratio (1:1); that is, the same number of pixels are used per inch both vertically and horizontally, regardless of how many inches high or wide a particular image may be.
Certain image formats, however, are encoded with a non-square pixel spacing ratio, typically YUV video (0.9:1) or "squeezed" anamorphic film footage (2:1). RAYZ uses the Pixel Ratio parameter value to display such imagery properly in the Image Viewer as well as to correctly perform rotations, blurs, and other image operations that may use image size data in the computation.
RAYZ sets the Pixel Ratio parameter automatically, based on the imagery being imported, but you can override the setting if RAYZ makes the wrong guess. The parameter value represents the variance, if any: for CG images and most film footage, the default value is 1; for video, it is 0.9; and for anamorphic, it is 2.
You will probably never want to change the default value (0) of this parameter. Common to all source nodes, it is described at the beginning of this chapter in Backing Color Parameters.
Some image file formats encode data in ways that require RAYZ to ask for additional information to interpret them properly. For example, some formats allow additional channels of data to be encoded at a different bit depth from the RGB image data in the same file.
When these files are imported into RAYZ, format-specific parameters become available as described below. Expand the parameter group to access the controls.
Fig. 14.20 Format-specific parameters only become active when an image of the corresponding type is imported--a Photoshop image in this example.
The Adobe Photoshop parameters become available when importing Photoshop (.psd) images, which may have been saved with multiple layers.
This parameter, which is checked by default, is equivalent to the "Flatten Image" command in Photoshop. It creates a single-layer image composed of all the layers in the Photoshop file. If you uncheck the box, RAYZ will read in only the layer specified in the associated Layer parameter.
This parameter becomes active when "Read Flattened" is unchecked. It enables you to specify which layer to read into RAYZ. Layers are specified by number, starting with 0 for the background layer.
The Maya parameter becomes available when importing Maya IFF imagery, which may include a channel of depth data, because Maya image files store RGBA data as 8- or 16-bits per channel and z-depth (ZBUF channel) data as floating point.
Read Data Menu: Use this menu to select whether to import the RGB(A) image or the z-depth channel into the current Image In node.
To access all channels of a Maya image (RGBZ or RGBAZ), select the same file sequence in two different Image In nodes and specify RGBA in the Read Data menu of one node, and ZBUF in the other. |
The Wavefront parameter becomes available when RLA or RLB files are imported, which may include specialized channels of data such as z-depth that are encoded at a different bit depth from the RGBA image data.
Read Data Menu: Use this menu to select which data to import into the current Image In node, the RGB(A) image, Z-Buffer channel, Effects channel, or Object channel.
YUV files are converted from YUV colorspace when imported into RAYZ. By default, they are converted to floating point data to avoid quantization.
This is because YUV data is encoded in a way that can result in values greater than 1 and less than 0 when converted to RGB, so the increased precision is necessary to avoid losing color information that would be clamped otherwise.
Represent As Menu: Use this menu if you need to change the bit depth from floating point to 8-bit or 16-bit per channel data.
The Image Out node is used to render the imagery flowing into it. Whenever you choose, the node will write image files to disk in the format and location indicated in the Image Out Node Panel. An Image Out node can be used at any point in a network, and you can add as many Image Out nodes to a network as you need.
Simply creating an Image Out node does not initiate rendering; however, you can start the render at any time by pressing the Render button at the top of the Image Out Node Panel. Alternatively, you can execute a render in the Render Control panel, which automatically lists all existing Image Out nodes in the project file and enables you to coordinate rendering of multiple sequences.
Each listing in the Render Control panel duplicates all the parameters in the Image Out Node Panel; in fact, the two sets of parameters are actually the same data, displayed in two different places. This means that you can make a change to a parameter in the Render Control panel and it will be reflected automatically in the Node Panel of the corresponding Image Out node, and vice versa.
See also Chapter 11: Rendering Images for more information.
The Image Out parameters are used to specify the filename and directory location, the file format, and the frame range to use for each render. In addition, you may be able to specify certain conversion or compression options for the selected file format.
Take advantage of the ability to save node presets to create Image Out presets for the combinations of parameter settings (such as a specific file path, format, and compression level) that you use frequently. Then you can select the preset from any Image Out node and the parameters will update accordingly. See also Presets Menu in chapter 7. |
The Render button at the top of the Node Panel is used to actually initiate a render. When you press the Render button, the node data is written to disk at the size and quality specified in the Scale Factor and Quality menus, and using the criteria specified in the other Image Out parameters.
The Scale Factor menu specifies whether the images should be rendered at full size or a fraction thereof. Full size is selected by default, however, you can choose to render Medium or Low size images instead.
By default Medium is 50 percent and Low is 25 percent of full size; however you can change these percentages in Edit > Project Settings > Settings > Scale Factors.
The Quality menu is used to specify a lower image quality render if necessary to reduce rendering time for preview comps. Quality is set to High by default, which renders the images at full quality.
The Medium and Low settings affect any filtering that has been specified in upstream nodes to reduce aliasing and related image artifacts, whether such filtering is user-set in a node parameter or is intrinsic to a node's operation:
Fig. 14.21 Parameters in the Image Out Node Panel. When you press the Render button at the top, RAYZ writes image files to disk in the location and format specified in the other parameters.
This parameter specifies the filename and location of the rendered image frames. You can type the complete pathname into the field or you can click the folder button associated with the field to access the file dialog and navigate the directory structure to the desired location:
Use the $F variable to sequentially number each frame file. To pad the frame numbers with leading zeros, append a number to $F to specify the number of digits. For example, using "comp.$F4.cin" as the filename would number the frames sequentially and pad each number with leading zeros as necessary to create a four-digit number: the first frame would be "comp.0001.cin," the second, "comp.0002.cin," and so on.
If you output a sequence as a QuickTime or FRP file, however, do not use "$F" in the filename since a single movie file of the sequence is being created instead of a series of frame files. |
You may also want to take advantage of the JOB global variable, which can be used in the Output Path field as shorthand for the directory into which the images should rendered.
For example, if you render a 200-frame sequence to disk and define the output path as "$JOB/my_file.$F4.tiff," RAYZ will create 200 files named "my_file.0001.tiff" through "my_file.0200.tiff" in the directory specified for $JOB.
The JOB global defaults to the directory from which you started RAYZ. You can redefine it to a different directory path in Edit > Project Settings > Globals. For more information about defining global variables, see Globals in chapter 13.
The Format menu specifies the image file format of the rendered imagery. Tiff format is the default; however, you can select any format from the menu. When you select another format, RAYZ will replace the .tiff extension in the File field with the appropriate extension for the chosen file type.
The same formats that can be imported into RAYZ can be specified. For a complete list, refer to Appendix B: Image File Formats Supported by RAYZ.
Be sure to review the sections below describing the Conversion parameters, which are used when the node imagery is linear and the render format is nonlinear, and the Format Specific parameters, which are used to set compression and other options when the corresponding render format is selected.
The Conversion parameters are used, when necessary, to specify how the node imagery will be converted to the file format selected in the Format menu. These parameters correspond to those governing the conversion of imported imagery in the Image In node.
Use this menu to specify the bit depth per channel at which to render linear imagery. The menu defaults to the bit depth of the node data, so you only need to use it when you want to change the bit depth.
As delineated in the guidelines under "Conversion" above, the Type menu is used to convert linear imagery to nonlinear, in conjunction with the file format chosen in the Format menu. The choices are as follows:
Select None unless you are converting linear node data to a nonlinear format.
Select To Log to convert linear node data to Cineon 10-bit log. (You must also select Cineon Fido or DPX in the Format menu.)
The Advanced parameters for Cineon conversion will become active, which are described in detail in the section of the Image In node description on Conversion Parameters.
Select To Video when you want to encode a nonlinear gamma correction in linear imagery to be rendered in a video format such as YUV. The Video Gamma parameter becomes active when this menu option is selected to enable you to specify the gamma value (the default is 2.2).
Unlike Cineon Fido format, which must be 3-channel, 10-bit log data, Cineon DPX files can be written that have 1, 3, or 4 channels, and they can be 8- or 16-bit linear, encoded with a non-linear video gamma, or they can be 10-bit log.
To write DPX files using the specifications you need, select the appropriate combination of conversion options from the Bit Depth and Type menus.
Expand this group to access parameters for controlling compression options. A parameter within the group becomes active when the corresponding file format is selected from the Format menu.
When rendering files in Adobe Photoshop, SGI, Softimage, or Targa format, you have the option to turn compression on or off (compression is on by default). When you render in JPEG, PNG, QuickTime or Tiff formats, you have additional compression options:
JPEG Format Compression: The JPEG format uses, naturally, JPEG compression. As JPEG is a lossy compression method, an additional parameter is provided to set the image quality level (the range is 0-100; the default value is 90). Image quality and compression level are inversely proportional: the lower the quality value, the higher the compression. For most images, the actual useful range is approximately 35-90 (with an image compressed to 35 being a very low quality image).
PNG Format Compression: The Portable Network Graphics format uses lossless Zip compression, with the option to set the level. Higher compression levels create smaller files but take longer to render.
QuickTime Format Compression: Uncompressed is selected by default, however you can choose Animation, YUV2, JPEG, or Motion JPEG-A from the QuickTime Compression menu.
Tiff Format Compression: In addition to turning off compression, you can choose from Zip, LZW (the default), or JPEG compression. Zip and LZW are lossless, with Zip providing the option to set the level of compression. The higher the compression, the longer the files take to render. If you choose JPEG to compress the files, you have the option of setting the quality level for this lossy compression method.
The Range parameters are used to specify the frame range to render. You can specify the start and end frame and the increment. By default the Range parameters are set to the range of the input sequence, with an increment of 1.
If the Overwrite box is checked (which it is by default), RAYZ will overwrite any files with the same name and location as the name you assign to the output files.
The Make Directories box, when checked (which it is by default), lets RAYZ create new directories, as needed, based on the directory path specified in each entry.
Some image file formats encode only color data; they do not support imagery with a separate alpha channel or other data. If you try to render node imagery containing more channels than the selected file format supports, RAYZ will generate an error message unless you check the Strip Off Extra Channels box. If this option is checked, however, RAYZ will ignore any extra channels and render the rest.
Certain file formats invert the orientation of images. Click the Vertical Flip checkbox to invert the imagery when writing the file to disk. This parameter is the complement to the Vertical Flip parameter for the Image In node.
The Stars node generates a star field based on actual astronomical data. You can set the node parameters to generate an accurate representation of the night sky that would be visible at a particular time and location, or you can simply experiment with the controls, judging the results by eye.
The data used to generate the positions, proper motions, and magnitudes of the stars is derived from the Smithsonian Astrophysical Observatory catalog. For more information about the SAO Star Catalog, refer to the following website:
http://tdc-www.harvard.edu/software/catalogs/sao.html
The frame parameters are described in Frame Attribute Parameters Common to Source Nodes. The parameters specific to creating the star field are described below.
Start by using the Position parameters to specify the time and location from which the sky would be viewed and then use the Look parameters to modify the appearance of the star field.
Use the Position parameters to specify from where and when the sky is being viewed (if an accurate representation is unnecessary or irrelevant, you can always use the default values). Start by selecting the coordinate system to use from the Coordinates menu and then set the other parameters, animating them as necessary:
The Tilt, Pan, and Roll parameters enable you to animate the star field, perhaps to "fly the camera" through space or to simulate changes in the sky over time from a single vantage point.
The Tilt (move in X) parameter can be adjusted in a range of -90 to 90 degrees, while you can Pan (move in Y) and Roll (move in Z) in a range of 0 to 360 degrees.
This menu specifies the order in which the above transformation operations will be computed. The default order is Pan, Tilt, Roll.
This parameter specifies the month of the year, from 1 (January) through 12 (December).
This parameter specifies the day of the month, from 1 through 31.
Right Ascension, abbreviated to RA, is the equivalent in the celestial sphere of longitude on Earth, but it is measured in hours, minutes and seconds instead of degrees.
The 0 hours line of RA marks the point where the sun crosses the celestial equator at the vernal equinox (the first moment of spring) in the northern hemisphere. Hours of RA are measured eastward from this point, up to 23 hours, 59 minutes. One minute later the cycle starts over at 0 hours.
Declination is the celestial equivalent of latitude. It specifies the angular distance, measured in degrees, above or below the celestial equator. It ranges from 0 at the celestial equator to 90 degrees at the north pole and -90 degrees at the south pole.
RA (Right Ascension) and Declination are the celestial equivalents of longitude (the lines that run East-West) and latitude (the North-South lines), the coordinate system used to specify locations on Earth.
Declination is a straightforward projection of the Earth's latitude into space. Terrestrial longitude, however, cannot simply be projected into space because the sky appears to rotate (15 degrees per hour, as the Earth rotates on its axis) with respect to any line of longitude on Earth.
For this reason, astronomers use a measure for celestial longitude called right ascension (abbreviated RA), in which the sky is divided into 24 fifteen-degree increments, each of which is one hour of right ascension.
This parameter creates an offset of the Y rotation value. The offset value range of 0-1 represents the percentage of one complete rotation (360 degrees).
Choose from Earthbound - Up (the default); Earthbound - North; Astronomical; or Ecliptic (Zodiac).
Use the Look parameters to modify the appearance of the star field. The fastest way to increase or decrease how "starry" the field looks is to adjust the Pre Gamma parameter. Related parameters include Magnitude, Over Exposure, and Softness. You can simulate lens distortions and similar effects using Focal Length, Film Size, Warp, and Pixel Ratio. The Saturation parameter controls the colorfulness of the stars.
Use this parameter, along with Film Size and Warp, to simulate the affect of changes in focal length or similar lens distortions. (Focal Length and Film Size are interdependent.)
The Film Size parameter is a scale factor for the Focal Length parameter, which means that when both parameters are at their default values (35), they have no effect on the node output. Changing the Film Size value creates a zoom effect.
The Warp parameter value changes the apparent depth of the star field, effectively adding curvature to the field.
Increasing the Softness value blurs and spreads the stars. This parameter works with the Anti-Aliasing parameter.
Use the Over Exposure parameter to change the average apparent magnitude values for the stars obtained from the database.
The Saturation parameter specifies how colorful the stars will be in a range of 0-1. The default value of 1 represents full saturation.
This parameter specifies a magnitude threshold value for the star field. Stars with magnitudes (as determined by the SAO database) below this threshold will not be represented in the output image.
This parameter changes the average brightness and size of the stars. It increases or decreases the magnitude values obtained from the database, which means that more stars will become visible as the Pre Gamma value is increased. (The Over Exposure parameter value will then further modify this characteristic.)
This parameter changes the default pivot value used by the Pre Gamma parameter.
Modifying this parameter will change the apparent width of the star field, squeezing or stretching it.
This parameter can be used to quantize the color values in each image channel when you want to reduce the total number of colors used per channel.
Use this parameter to specify the level of anti-aliasing used.
This menu specifies which anti-aliasing method to use: Runge's Original, which refers to the algorithm used by the author of this node, Dirk Runge, or a Gaussian blur. Try Runge's Original first; it usually produces an optimal result for a star field.
The Turbulence node generates a pattern simulating turbulence from a solid field of color by altering the value and opacity of each pixel as specified in the Node Panel.
Turbulence includes controls for creating the turbulence pattern and for specifying the output frame attributes. The frame parameters are described in Frame Attribute Parameters Common to Source Nodes. The parameters specific to creating the turbulence pattern are described next.
Use the Type, Speed, Detail, and Seed parameters to create the pattern and the Color parameters to change the default color.
The Color parameters are used to change the default color field from which the other parameters generate the turbulence. The default color is white (the maximum RGBA values for the specified bit depth), which results in a grayscale turbulence pattern.
Whichever color you use, each channel is adjusted equally for each pixel so that only the luminance changes, not the hue. For more information about using the controls, see Using the Color Parameters.
Select the type of turbulence to create from the Type menu: Simple (the default), Formica, Clouds, or Marble.
Fig. 14.22 Examples for the four types of turbulence, with other parameters at their default settings. Clockwise, from upper left: Simple, Formica, Marble, and Clouds.
Use the Speed parameter to change the slope of the "hills and valleys" of the turbulence pattern. Try experimenting with this control until you see the desired result.
When any type of turbulence other than Simple is selected, the Detail parameter becomes active. As the name implies, increasing the value of this parameter increases the level of detail in the pattern; decreasing it lowers the level of detail.
Use the Scale parameter to increase the default scale factor from 1; the range is 1-10. Larger scale values will, in effect, "zoom out" of the turbulence pattern.
The Seed parameter is used to animate the starting value for the turbulence pattern to produce a changing pattern across time.