Chapter 6: Using the Image Viewer

The Image Viewer is used for every image display task in RAYZ, whether you want to view a single frame or play back a sequence.

You can evaluate an image at any frame of any node in the shot and adjust the various parameters in the Node Panel accordingly, modifying the effect until you are satisfied. Display of the image frame or flipbook will update automatically with every modification (unless you choose to turn off this option and update manually).

The Image Viewer has two separate buffers for comparing imagery and provides overlays and inspection tools you can use to evaluate the current image. Some overlays are interactive tools that can be used in lieu of Node Panel parameters to modify imagery.

In This Chapter

Displaying Images

Main Viewer Controls

Viewer Tools Panel

Viewer Overlays

Comparing Images

Running a Flipbook

Defining a Region of Interest

The spatial resolution of the image displayed is independent of the size of the view frame, which can be resized or maximized, and the viewspace under the view frame is effectively infinite.

By default, the background color of the viewspace, which is visible surrounding the image, is black. You can specify that the Image Viewer use a different color by changing the Outside Image Color preference setting in Edit > Preferences > Settings > Image Viewer. For more information, see Image Viewer Settings in chapter 13.

Active Area

When image pixels are transformed out of frame they are not discarded, which means that they can be transformed back into frame later, and that the frame size itself can be redefined later.

The area that encompasses all pixel data at a point in time is called the active area to distinguish it from the output frame area . Viewer Overlays explains how to turn on visible borders representing the active area and frame area, and Fig. 6.15 illustrates the concept.

Viewer Tools

The Image Viewer provides several control strips, each with its own set of tools for adjusting how an image is displayed or for getting information about specific pixels in the image:

Image showing the Image Viewer with tools labeled.

Fig. 6.1 Tool strips available in the Image Viewer.

Any tool strip can be accessed from the Tools menu in the title bar of the Viewer.

Image showing the contents of the Image Viewer Tools menu.

Fig. 6.2 If an item in the Tools menu of the title bar is checked, the corresponding tool strip will appear in the Viewer.

As with other types of view, you can choose whether or not to display a tool strip and you can reposition a tool strip by dragging it to a different edge of the view frame. If you need more information about this, refer to Changing the Layout of View Elements in chapter 4.

The shutter control on the Viewer Tool Panel is especially useful for stowing the panel temporarily when you need more Viewer real estate to display a large image. The shutter control is described and illustrated in Working with Tool Panels in chapter 4.

Displaying Images

By default, the front buffer (the main buffer) of the Image Viewer displays the RGB data for the node that is currently selected in the Worksheet, at the frame currently specified in the Time Scooter. However, you have a number of options for the display of images in the Viewer.

You can view any channel in the image, or a channel based on luminance values, by selecting it from the Channel Menu.

When working with large images, you can display them at a lower resolution by selecting one from the Size Menu. And ROI can be used to confine processing to a limited area of a large image.

You can use the middle mouse button to drag the image around when it is larger than the current view frame. In addition, you can resize or maximize the Image Viewer to display more of a large image. You can also Zoom in and out.

Full Screen View Mode:

To fill the screen with the contents of the viewspace; that is, to maximize the Viewer and black out the view frame so that only the image is visible, switch to Full Screen mode by pressing the n key . This hotkey is a toggle; press n again to switch back to the full layout.

Tip:

 

Press the (numeral) 1 key while the cursor is hovering over a node to launch a new Image Viewer window with that node image displayed in it.

By default, RAYZ will update the image displayed in the Viewer after every parameter modification, but you can specify Manual, Automatic, or Continuous Update mode for each buffer as described in Front Buffer and Reference Buffer.

RAYZ selects the display LUT to use for an image automatically, based on the type of image data it is. However, you can override the automatic setting or add your own custom lookup tables, as described in Display Conversion.

Displaying Node Input or Output

Depending on the type of node, you also have the option of viewing either the image that will be output by the node or any of the node's input images. This enables you to view the image before and after modification.

Some nodes actually display an input image by default. In the Ultimatte nodes, for example, you start by using an eyedropper tool to sample an area in the bluescreen backing of the primary input.

Use the Source Menu, which lists all available options for the current node, to select an input or the output for viewing.

About the Image Buffers

The Image Viewer has two image buffers, the front buffer and the reference buffer. The front buffer is the main buffer and all Viewer functions are available to use with it.

The reference buffer, on the other hand, has a more limited purpose--to provide an image for comparison with the image in the front buffer. In particular, the reference buffer can never follow the current node selection in the Worksheet.

 See accompanying caption for image description.

Fig. 6.3 Front and Reference Buffer Buttons: the reference buffer remains empty (as indicated by the question-mark icon) until you drag and drop a node onto the Reference Buffer button.

The F8 hotkey toggles the display back and forth between the front and reference buffer images. Use the Wipe controls to wipe between the two buffers, as described in Comparing Images.

Pinning an Image to the Front Buffer

You can pin the front buffer to the current node image, if you wish, so that the Viewer no longer follows the node selections in the Worksheet but continues to display the node image to which it is pinned.

To pin the image currently in the buffer, click the Pin icon in the Viewer title bar. To pin a different node image, drag the node over the Image Viewer and drop it (release the mouse button).

To enable the buffer to follow the current node selection again, click the Pin icon in the Viewer title bar. For more information, see also Dynamic Focus in chapter 4.

Filling the Reference Buffer

The reference buffer, which is used to hold a separate image that can be compared with the image in the front buffer, is empty by default. Unlike the front buffer, it does not follow the current node selection.

To add an image to the reference buffer, drag a node over the Reference Buffer button in the Viewer Tools panel and release the mouse button. The image will remain in the reference buffer until you clear it by selecting "Clear Buffer" from the Reference Buffer menu.

See also Buffer Controls.

Main Viewer Controls

The Main Viewer control strip provides core image display tools to specify the channel to display, at what resolution, zoom level, and even pixel ratio when relevant. Most of these tools can also be controlled using hotkeys.

Image showing the tools available in the main control strip of the Image Viewer.

Fig. 6.4 Controls in the Main Viewer control strip.

Front and Reference Buffers

To accommodate wipes between the image buffers, the Zoom, Size, and Pixel Ratio settings apply to both buffers.

Front Buffer Only

The Channel, Source, Manual Update, and ROI controls, on the other hand, can only be used on the front buffer image. The Reference Buffer in the Viewer Tools panel provides separate channel selection and update controls for the reference image.

Channel Menu

Use the Channel menu to select which channel or channels of the image to display. The default is RGB, however you can select any individual color channel, luminance, or the alpha channel, if there is one.

Hotkeys:

 

With the cursor over the Viewer, press the c key for RGB display (think "color"), a to view the alpha channel, or r , g , or b for the red, green, or blue channel respectively. For luminance, press the letter l . If the image has a fifth channel, as for z-depth data, press the o key (for "other").

Zoom

The zoom menu enables you to zoom in on or out of the image by selecting a zoom factor from the menu or using the hotkeys.

Hotkeys:

 

Use the Plus ( + ) and Minus ( - ) keys to scale the image in discrete increments. Press the Minus key to zoom out of the image and the Plus key to zoom in. (Technically, you use the "equal sign" key to zoom in; that is, you do not have to hold down the Shift key as you press the Minus key.)

Alternatively, you can hold down the Ctrl key while dragging with the middle mouse button. Ctrl-middle-drag up or right to scale up; down or left to scale down.

Size Menu

Use the Size menu to select the display resolution for the image: Full, Medium, Low, or Fit. Full displays the image at full spatial resolution, while Medium and Low scale the image down to specific fractions of full size. Fit scales the image to fit the current size of the Viewer.

By default, Medium is half and Low is a quarter of full resolution. You can change the scale factors in the General Preferences panel, which is described in the section on Settings in chapter 13.

If you have proxy image files specified in the Image In node, the Viewer will use them for Medium and Low display. Otherwise the full size imagery will be scaled down. For more information, refer to Using Proxies in RAYZ in chapter 10.

ROI

This menu controls ROI, which is used to define a "region of interest." Only pixels inside the region will be processed and updated in the Viewer. Refer to Defining a Region of Interest for more information.

Pixel Ratio

The Pixel Ratio menu becomes relevant when you are displaying anamorphic film footage or certain video imagery that appears squeezed in the Viewer. (Refer to Image Description Parameters in chapter 14 for more information about images with non-square pixel spacing ratios.)

The menu has three choices:

Both Cheap and Accurate unsqueeze the image display, and if your anamorphic footage, for example, has a 2:1 pixel ratio they are equivalent choices. If it has a pixel ratio other than 2:1, however, the choice does make a difference. Cheap will be faster but will give you an approximation, while Accurate will take longer to calculate but will display the exact ratio of your imagery.

Manual Update Button

Whenever manual update mode is in effect for the front buffer, the Manual Update button in the Main Viewer control strip is activated. In manual mode, the image is not updated to reflect changes to node parameters until you press the Update button.

Hotkey:

 

Press the y key to update the front buffer image when in Manual Update mode.

To change the update mode, select Manual, Automatic (the default), or Continuous from the Update mode menu located in the Front Buffer of the Viewer Tools panel.

Source Menu

The Source menu is used to select whether the Viewer should display the input image or the node output image. For most nodes, the default selection is Output, which shows how the image will look after processing by the current node.

If the node has multiple input images, this menu will list them also. For example, you can switch from viewing the node output to viewing the primary input image or the mask input image.

Image showing an example of the display options available from the Source menu in the Image Viewer.

Fig. 6.5 Source Menu: This image illustrates the options available for the Ultimatte CSC node, which uses a primary input image and clean plate input image.

Hotkey:

 

Press the s key to change the current Source menu selection. If the Source menu contains more than two options, you can press the key repeatedly to cycle through all the choices.

Autokey

The Autokey controls are identical to, and linked to, the Autokey function in the Node Panel. They are duplicated in the Viewer for convenience, and they become active whenever a node image that uses overlays is displayed in the Viewer, or whenever the Node Overlay Buffer is used. The overlay buffer takes precedence, which means that the Autokey controls apply to the node in the overlay buffer, if any, rather than the node displayed in the front image buffer.

You turn on Autokey mode to tell RAYZ that you are animating parameter values across time. The Autokey arrow buttons navigate directly to the next or previous keyframe. For a complete description, refer to Using Autokey Mode in chapter 7.

Viewer Tools Panel

The Viewer Tools panel provides interactive image inspection tools such as a pixel value reader and a color picker, which can be used on the front buffer image only. The panel also provides a display conversion toolset and update options for both image buffers. The Viewer Tools menu is also where buffer assignments are controlled.

Live Color Display

This group of pixel inspection tools displays the color value and position of the pixel currently under the cursor in the front buffer image. As you move the cursor over the image, the readout updates accordingly:

Image showing how the Color Values tools display color and position data about pixel under the cursor.

Fig. 6.6 Live Color Display shows the RGBA values and x,y position of the pixel under the cursor.

By default the values are displayed at native bit depth as RGB data (this is the "RGB Native" option in the menu). However, you can change the colorspace units to use by choosing another option.

Color Picker

The Color Picker group includes an eyedropper tool for interactively picking a color in the image currently being displayed in the front buffer . (See also Buffer Assignments.)

Image showing the color picker tools in the Image Viewer.

Fig. 6.7 Color Picker: Use the eyedropper to pick a color from the image using the sample method selected in the associated menu. The color is stored in the selected color swatch. The RGB values are displayed at the bottom in the units selected from the Readout menu.

The menu next to the eyedropper is used to specify how and what to sample. The sampled value is stored in the selected color swatch, and there are 8 swatches in which you can store color values.

Eyedropper Tool

Use the eyedropper tool to pick a pixel:

  1. Select a sample method from the menu (see below).
  2. Click the eyedropper once to select it. (The cursor will change to an eyedropper icon.)
  3. Move the eyedropper cursor over the pixel(s) you want to pick and click, scrub, or drag, depending on your selection in step 1.

The color you sampled will appear in the selected color swatch.

Sample Method Menu

Use this menu to select the sample method to use. There are two sample methods: Click/Scrub and Drag Box. And for each sample method you can choose whether to get the average value, the maximum value, or the minimum value of the pixels you sample:

Color Swatches

The Color Picker also includes a group of color swatches, which work like all other color swatch palettes in RAYZ. When you use the eyedropper tool to sample the image, the color is stored in whichever swatch is currently selected, replacing the previous color. Click any swatch to display its color values in the readout.

You can also change the value stored in a swatch by right-holding on the swatch to access the popup spectrum bar. Drag the cursor across the spectrum to select a color and release the mouse button.

Tip:

 

You can change the default colors used for a project, as when it would be useful to store project-specific reference values in some of the swatches. Choose Project Settings from the Edit menu, expand the Current Colors group, and select Image Sample Color Palette to display a list of swatches. Then select any swatch to edit it.

Readout

Use the Readout menu to select the colorspace units in which the selected color values should be displayed. The default is RGB Native, which displays the RGB values in the native bit depth of the image, but you can also choose RGB Float or RGB Log. Additionally, you can choose to display the values in their equivalent units in HSL, HSB, HWB, YIQ, or YUV.

Buffer Controls

The Viewer Tools panel includes display controls for the front and reference image buffers, as well as the buffer assignment tools.

Front Buffer

Image showing the Front Buffer Controls.

Fig. 6.8 Front Buffer Controls.

This group of controls is used to set the image update mode and type of display conversion to use for the front image buffer.

Image Update Mode

By default, the image in the front buffer updates automatically; however, you can use the menu to select Continuous updates or Manual updates instead:

Hotkeys:

 

To switch the front buffer to Auto Update mode, press Shift-a ; to switch to Continuous Update, press Shift-c .

Display Conversion

These parameters control how the image data in the associated buffer is interpreted for display in the Image Viewer. It is never strictly necessary to adjust these parameters, because RAYZ selects the appropriate type of display translation automatically, based on the data type (linear or log) and any custom gamma information you have specified in the Image In node. (For more information on these Image In node settings, refer to the section on Conversion Parameters in chapter 14.)

Image showing the Display Conversion parameter group expanded.

Fig. 6.9 Display Conversion parameters set to manual mode, with Low High Gamma parameters available for modification.

Cineon Log Display

By default, the Image Viewer displays log image data using Raw Log . The Raw Log display LUT simply shifts the log values up in the linear colorspace to make them visible; it does not attempt to remap the nonlinear distribution curve. Log images displayed this way tend to look washed out in the Viewer.

You can also display a log image using Cineview Emulation , which will give you a better idea of what the image "should" look like, by turning off Automatic display conversion and selecting the Cineview option from the Display Conversion menu. See Fig. 6.10 below.

Cineon imagery that has been converted to a linear format is displayed by default using the Low High Gamma settings, with the RGB Gamma set to the corresponding value that was specified when the image was converted (which is 1.7 by default).

Image showing the contents of the Display Conversion menu.

Fig. 6.10 The Display Conversion menu includes Cineview and Raw Log display emulation.

Automatic checkbox

You can override the current display settings by turning off the Automatic checkbox. This activates parameters you can use to select a specific LUT (lookup table) or other type of display emulation, or to manually adjust the Low, High, RGB Gamma, and Other Gamma display values.

RGB and Other Gamma

The RGB Gamma setting affects the display of the RGB channels only, while the Other Gamma setting affects the gamma value used to display the Alpha or other channel, if the image has one.

LUTs

Image showing the LUT File parameter.

Fig. 6.11 The File parameter appears when LUT File is selected in the Display Conversion menu.

Select LUT File from the Display Conversion menu (uncheck the Automatic box to access) to use an existing LUT file that is not in the menu list. The LUT File parameter will become active, in which you can specify the pathname of the LUT file you want to use.

LUT files should be plain text files that follow the guidelines in Appendix F: LUTS.

Custom LUTs:

You can also create custom LUTs for use in RAYZ by writing a plugin of the appropriate type, which will then appear in the Display Conversion menu. For an example, refer to the file CPI_LUTProvider.h, which is located in the following directory:

/usr/grail/rayz2.2/support/plugIns/include

Reference Buffer

Image showing the Front Buffer Controls.

Fig. 6.12 Reference Buffer Controls.

This group of controls is used to select the source image and channel to display, and to set the image update mode and display conversion for the reference image buffer.

The Channel menu for the reference buffer works just like the one in the Main Viewer Control strip that is used for the front buffer image. The default is to display the RGB image, however, you can select any channel in the image for display.

The Source menu for the reference buffer (eye icon) also works like the one use for the front buffer image (see Source Menu). The output image is displayed by default.

The Image Update mode menu is also identical to the one used for the front image buffer (see Image Update Mode) to select Automatic, Continuous, or Manual update modes.

If you select Manual update mode for the reference image, however, use the Update button in the Reference Buffer controls to update the reference image manually. The Update button in the Main Viewer control strip is for the front buffer only. Also, be aware that the hotkeys for updating apply only to image in the Front buffer.

The Reference Buffer control group also includes the same tools for Display Conversion that are included in the Front Buffer controls.

Buffer Assignments

Image showing the Buffer Assignment controls.

Fig. 6.13 Buffer Assignment Controls: This example shows a Multi-comp node image in the front buffer, an Ultimatte image in the reference buffer, and the Roto node overlays in the overlay buffer.

The Buffer Assignment buttons show which node image or overlay, if any, is currently in the front image buffer, reference image buffer, and overlay buffer. The Reference Buffer and Node Overlay Buffer buttons also act as targets onto which you drag and drop the node whose image or overlay you want to add to that buffer.

Front Image Buffer

The Front Buffer button indicates which node image is currently displayed in the front image buffer, and it updates automatically as you select different nodes in the Worksheet (unless you have pinned the image, as described in Pinning an Image to the Front Buffer).

Reference Image Buffer

To add an image to the reference buffer, drag and drop a node over the Reference Buffer button. To assign a different image to the reference buffer, drag and drop a new node into it. To empty the reference buffer, select Clear Buffer from the popup menu (hold down the buffer button to access).

The reference buffer can hold a different node image than the one in the Front buffer, or it can hold the same node image, so that you can wipe between

See Comparing Images for a description of the Wipe controls and how to perform the types of wipe listed above.

Node Overlay Buffer

Many nodes feature overlays and other controls that appear in the Viewer whenever the node is selected. (See also Node-Specific Controls and Overlays.) In some cases, however, you may want to manipulate a node overlay while viewing an image from another node. For example, you might want to adjust a spline created in a Roto node to fix a foreground matte while viewing the image as it appears composited over the background in a Multi-comp node.

The node overlay buffer is designed for just that purpose. You can drag and drop any node that uses overlays onto the Node Overlay Buffer button to make the overlay available for use in the Viewer when the node image is not currently being displayed.

The overlay buffer is empty by default. When you drag-and-drop a node into it, the node name appears in the buffer. To assign a different node overlay to the buffer, drag and drop the new node onto the Node Overlay Buffer. To clear the overlay buffer, press the Clear button on the right.

Note:

 

When a node that features overlays or other node-specific Image Viewer controls is displayed in the front buffer, its overlay controls appear in the Viewer automatically-- it is not necessary to assign the node to the overlay buffer; in fact, the node overlay buffer remains empty in this case.

Viewer Overlays

You can turn various image overlays on and off in the Image Viewer. An overlay is an object that is drawn over the image, such as borders that delineate the title safe areas of the frame or the output frame area itself (see Border Display Overlays).

Some overlays, such as the Image Profile Overlay and Magni-zoom Overlay, update dynamically as you move the cursor.

Two overlays are used to edit boundaries--one defines ROI (see Defining a Region of Interest) and the other defines the area used for a Region Wipe.

Image showing the contents of the Viewer Actions menu.

Fig. 6.14 The Viewer Actions popup menu is used to turn the display of any overlay on or off.

The overlay display controls are in the Viewer Actions menu, which is accessed by holding down the right mouse button anywhere in the viewspace.

The Node Controls item at the top of the menu controls the display of node-specific overlays, which vary depending on the node image being viewed, as explained in Node-Specific Controls and Overlays.

As an alternative to using the Viewer Actions menu, you can define a hotkey to control the display of any overlay by selecting the overlay in the Hotkeys list in Edit > Preferences. For more information, refer to Hotkeys in chapter 13.

Tip:

 

You can change the default colors used to draw the overlays if necessary to make them stand out better over your imagery.

Select Project Settings from the RAYZ Edit menu and expand the Current Colors group in the left pane to select the Overlay Gadget Color Palette preferences. Then you can edit the default color values for any of the overlay components listed in the right pane.

Border Display Overlays

Some overlays delineate the borders of the frame or other areas of the image. You can display a border around the Full Size area (the frame output) and the Active Area (a rectangle encompassing all pixels with non-zero values). This concept is explained in Active Area.

Image showing the Full Size and Active Area overlays in the Image Viewer.

Fig. 6.15 The Full Size overlay (solid white line) delineates the output frame area, while the Active Area overlay (dotted line) delineates the area that includes pixels subject to modification.

Video Safe

The Video Safe overlay outlines the title safe and action safe areas of a video frame.

Field Chart

The Field Chart overlay can be used to conform titles to film formats with a 4:3 aspect ratio by referencing the 12 standard field sizes demarcated on the overlay grid. In addition, several other aspect ratios are also outlined on the chart.

Fig. 1.85 Mask

The 1 .85 Mask overlay masks out the top and bottom of an Academy aperture image so that you can see what will be lost in so-called flat widescreen format, which has a 1.85 aspect ratio.

Magni-zoom Overlay

Image showing the use of magni-zoom feature in the Image Viewer.

Fig. 6.16 Magni-zoom Overlay.

In effect, Magni-zoom turns the cursor into a magnifying glass that provides a close-up view of a rectangular area centered under the cursor.

The Magni-zoom overlay moves with the cursor and enables you to examine image areas in detail without zooming the entire image.

Hotkey:

 

You can use the m hotkey to toggle the Magni-zoom overlay on and off.

Magni-zoom will magnify whatever pixels are under the magnification box, whether the image displayed is in the front or reference buffer.

Tip:

 

Magni-zoom works with interactive node overlays, which means that you can turn this feature on as you manipulate a roto spline handle or transform widget, if necessary, to make it easier to see and adjust.

You can change the level of magnification and the size of the magni-zoom area in Edit > Preferences > Settings > Image Viewer. (For general information about changing preference settings, see also Editing General Preferences in chapter 13.)

Image Profile Overlay

The Image Profile overlay is a graphical representation of image values that updates dynamically as you move the cursor over the image. This overlay graphs the values each channel of each pixel in a horizontal and vertical "slice" along the axis currently under the cursor.

Image showing an example of the Image Profile graph in the Image Viewer.

Fig. 6.17 The Image Profile overlay generates a dynamic graph of the pixel values. Note the hot spot identified in the highlights on the model's hair.

Node-Specific Controls and Overlays

Some overlays are node-specific; that is, they are only applicable if a particular node image is being displayed. Most node overlays are interactive tools. They may have handles that can be manipulated by dragging or they may be accompanied by a control strip.

Image showing the Transform node overlay in the Image Viewer.

Fig. 6.18 The Transform widget is a typical type of node overlay.

For example, the interactive transform overlay is available in nodes that perform spatial transformations.

And the Roto control strip, which contains the mode buttons used to draw and edit roto shapes, is available when a Roto node image is being displayed. The roto splines themselves are node overlays.

The use of each specific node control strip or overlay is explained in the individual description of that node in Part III: Node Reference.

Comparing Images

In addition to the main image buffer (the front buffer), the Image Viewer provides an additional reference buffer to use for comparing two different images. (See also About the Image Buffers.)

Whenever you have an image in both buffers, you can toggle back and forth between them using the F8 function key. The Wipe control strip also becomes active, however, so that you can perform various wipes between the two buffers.

Wipe Controls

To wipe between the front and reference buffer image, just drag the slider. The farther left you drag the slider, the more of the front image you see; the farther right you drag it, the more you see of the reference image.

Image showing the Wipe control strip.

Fig. 6.19 Wipe Controls: The image in the front buffer ("blur1") is labeled on the left side of the slider; the reference buffer image ("grad1") is labeled on the right side.

Wipe Buffer Buttons: F and R

When you have a wipe position set, you can temporarily display the entire image in the front or reference buffer without resetting the wipe point: Hold down the F button to see the front buffer image; hold down the R button to see the reference buffer image. When you release the mouse button, the wipe image will reappear.

Wipe Types

A horizontal wipe is selected by default, but you can also select vertical, top diagonal, bottom diagonal, dissolve, diamond, iris, and region, or no wipe at all.

Image showing the wipe menu selections.

Fig. 6.20 Hold down the Wipe button to access the menu and select the type of wipe to use.

Region Wipe

This type of wipe enables you to drag a rectangular "hole" over the top image through which you can see the bottom image.

When you select Region Wipe from the Wipe menu, a crop box overlay appears. Drag the sides or corners of the box to resize it to suit your current need.

To wipe, just click anywhere inside the region and drag.

You can hide the overlay box without turning off the region wipe. Right-hold in the viewspace to access the Viewer Actions menu and deselect Edit Wipe Region. If you need to change the region area, just reselect it.

Wiping Between a Node Input and Output

You can wipe between a node's output image and its input image:

  1. Put the same node that is in the front buffer into the reference buffer (as described in Filling the Reference Buffer).
  2. Use the Source Menu to switch the front buffer display to the input image.

Then you can use any of the wipe methods described in Wipe Controls to wipe between them.

History Wipes

You can wipe between the same node image before and after modifying a node parameter:

  1. Put the same node that is in the front buffer into the reference buffer (as described in Filling the Reference Buffer).
  2. Switch the Update mode for the reference buffer to Manual so that it will not update unless you force it to do so. The Update menu for the reference buffer is located in the Viewer Tools panel, as illustrated in Fig. 6.12.

Then you can make further changes to parameter values and see the result in the front buffer image, while the reference buffer image retains the "before" image.

Running a Flipbook

In addition to displaying individual image frames, you can also play entire sequences (flipbooks) of node imagery in any Image Viewer.

Playing a sequence is as simple as pressing the Play button. All channels are cached, which means that you can still switch from, say, RGB to alpha channel display as the flipbook is running.

If the reference buffer also contains an image sequence, it will be played also so that you can wipe between the sequences as they play, assuming you have enough RAM. If you do not, you can always clear the reference buffer before pressing Play or accept slower playback.

About Caching and Playback

Depending on the size and number of frames, and the system on which RAYZ is running, you may have to wait until all of the frame images are cached into RAM the first time before the sequence plays back at full speed. Frames cached in RAM are indicated by blue markers running along the top of the Flipbook slider, as illustrated in Fig. 6.24.

You can change the zoom level without affecting the cache, but changing the setting in the Size menu will cause the sequence to be recalculated.

Note:

 

Unless the Image Viewer is pinned to the cached sequence, the cache will be cleared when you select another node in the Worksheet and you will have to re-cache the sequence to play it again.

To avoid this, you can pin the Viewer containing the flipbook and create another Image Viewer to display other nodes.

Disk Caching

If RAYZ has to resort to disk caching, you may not achieve real-time playback. The actual playback rate is indicated in a readout to the right of the FPS parameter (where you specify the desired playback rate).

Continuous Updates

In continuous update mode, you can modify node parameters while the flipbook is playing and the sequence will update as it plays. It will attempt to update at the frame rate specified in the FPS parameter, but the actual speed will depend on the imagery, the operation, and your hardware.

Flipbook Control Strip

You can specify which frames to play at what increment and frame rate, and you can play the sequence once or continuously, forward or backward, or scrub using the controls available in the Flipbook control strip.

Image showing the Image Viewer flipbook controls.

Fig. 6.21 Flipbook Control Strip.

Transport Controls

The Transport control buttons are used to start and stop playback.

Image showing the transport controls in the Flipbook.

Fig. 6.22 Transport Control Buttons.

The Play Forward and Play Backward buttons play the entire sequence. Press the same Play button again to stop playback. (The Play button turns into a red Stop icon while a sequence is playing.)

The sequence plays once or continuously based on the type of looping specified, as well as the increment and FPS settings.

Hotkeys:

 

You can use the j and k hotkeys to control playback. The k key is equivalent to Play Forward and the j key, to Play Backward. These keys are toggles, so to stop playback simply press the hotkey again.

You can also use the Flipbook Transport controls in lieu of the frame navigation buttons in the Time Scooter. The Next Frame and Previous Frame buttons to step forward or back a frame at a time. To go directly to any specific frame, type the frame number into the Current Frame field.

Hotkeys:

 

Use the , and . hotkeys to go to the next (period key) or previous (comma key) frame. Shift-, takes you to the first frame; Shift-. takes you to the last frame.

Slider Controls

You can drag the slider bar across the Flipbook slider to navigate through a sequence of frames. You can also simply move the mouse over the slider: As you move, the number of the frame that would be selected if you clicked that location appears next to the cursor; when the frame number you want appears, click on the slider to go to that frame.

Image showing the slider controls in the Flipbook.

Fig. 6.23 Flipbook Slider.

Using the Slider to Scrub

Drag back and forth in the Flipbook slider to scrub in the sequence. Once the image data for all the frames you are scrubbing has been cached into RAM, you will get a smooth effect.

Image showing the cached frame indicator in the Flipbook.

Fig. 6.24 Frames that have been cached into RAM are indicated by blue tick marks at the top of the slider.

Frame Range

The First Frame and Last Frame fields, located at either end of the slider, are used to specify the range of frames to play. They default to the global time defined in the Time Scooter, but you can change the range by typing new values into the Start and End fields or by using the Fit Range button.

Image showing the slider controls in the Flipbook.

Fig. 6.25 Fit Range button (far left) can be used to set the Start and End field values.

Fit Button

Press the Fit button to set the frame range to match the length of the node sequence currently displayed in the Viewer.

Increment

The Increment value is set to 1 by default, which includes each frame in the playback. If you set the increment to 2, every other frame will play, and so on.

The hotkeys used to go to the next (Period key) or previous (Comma key) frame follow the current increment setting. That is, pressing the "go to next frame hotkey" will take you to the next frame available at the current increment (assuming the cursor is over the Image Viewer).

Loops

This menu is used to specify whether the sequence should play once or continuously when you press a Play button.

Image showing the contents of the Loop style menu, with icons labeled.

Fig. 6.26 Options available in the Loops menu include Play Once (no looping), Cycle loops, and Bounce loops.

There are two styles of continuous playback, or loop, to choose from:

Frame Rate (FPS)

This data entry field is used to specify playback speed in frames per second. The default is 24fps, but you can type a different value (such as 30fps for video) in the field or use the FPS menu to select 12, 24, 30 or 60.

You can change the default FPS value to match your project as described in Editing Project Settings in chapter 13.

Actual Rate

The first time you play a sequence, playback may be slower than the specified rate as RAYZ computes the frames and caches the data in RAM. Subsequent loops will play at full speed, assuming you have enough RAM to hold all of the frames. If not, RAYZ will resort to disk caching, and you may not achieve realtime playback.

The "Actual" readout to the right of the FPS field shows the actual playback rate achieved.

Defining a Region of Interest

ROI, or region of interest, is used to define an area of an image for display and updating in the Image Viewer. Using ROI can save time when working with large format imagery because RAYZ will not update the entire image display, just the region you need to evaluate:

Image showing effect of using ROI in Image Viewer.

Fig. 6.27 Sphere is being transformed out of frame, as indicated by the white box outlining the frame border (left). ROI is used (right) to define entire active area as region of interest, so that even those pixels outside the frame border are displayed.

Image areas outside the region of interest will still be visible when you switch to ROI mode, but they will not update as node parameters are modified. This enables you to use the entire image as a reference when defining and updating a region.

Using the ROI Controls

  1. Select Edit from the ROI menu to display the overlay used to define the region of interest.
  2. Drag the borders to resize the box; drag anywhere inside the borders to reposition it over the image.
  3. Then, optionally, you can hide the overlay while remaining in ROI mode by selecting Active from the ROI menu.
  4. To return to normal display mode, Select Off from the ROI menu.

Edit Mode

When the ROI menu is set to Edit mode, a bounding box overlay appears on the image. (You can also use the Viewer Actions menu to turn the ROI Edit overlay on and off without turning off ROI mode.)

Image showing the ROI menu in Image Viewer.

Fig. 6.28 The ROI menu is located in the Main Viewer Control strip.

To define the region of interest, drag the overlay edges or corners to resize the bounding box and drag anywhere inside the box to reposition it over the image.

Active Mode

If you find the overlay distracting, you can switch the ROI menu to Active mode, which hides the overlay box while remaining in ROI mode. If you need to adjust the region of interest, you can always switch back to Edit mode.