The Curve Editor is used to animate parameter values across time. Parameter data is displayed as a waveform, or "curve," in the Curve Editor graph, which plots the parameter's value across a range of frames.
You can control which curves are displayed in the graph, add and delete keyframes and adjust their value, and apply different distribution functions to curves to control the interpolation of values between keyframes.
Unlike the Node Panel, the Curve Editor view is able to display parameter data from more than one node. This enables you to compare and copy curves from one node to another.
Fig. 8.1 All nodes selected in the Worksheet (top) are added to the Curve Browser list (lower left).
By default, the Curve Editor displays parameter data for the node or nodes currently selected in the Worksheet.
To remove a node from the Curve Browser list, press the Delete button ("X" icon) at the right side of the node entry.
You can also pin a node to a Curve Editor, if you wish, so that the Curve Editor will no longer follow the current selection in the Worksheet. Pinning any node to the Curve Editor will actually pin all nodes displayed in the Curve Editor at that time. For more information, see Dynamic Focus in chapter 4.
Press the 3 key while the cursor is hovering over a node to launch a new Curve Editor window with that node data displayed in it. |
The Curve Editor graph displays a curve for all node parameters specified in the Curve Browser.
Fig. 8.2 Curve Editor Graph: horizontal axis represents time; vertical axis, value.
In the graph, the horizontal axis represents time, expressed in equal increments of frame numbers, and the vertical axis represents the range of parameter values being plotted. The current frame specified in the Time Scooter is indicated by a vertical blue line.
You can reposition the graph in the view frame and scale the graph up or down to get the best view of your curve data. In most cases the Fit button is the best option, however, you can also manipulate the graph directly.
The Fit button is located in the bottom right corner of the Curve Editor graph. When you click it, the graph is scaled to fit all of the curves into the currently visible graph area.
You can move the graph around in the view frame by middle-dragging in the background. Alternatively, the horizontal time scale at the bottom of the graph and the vertical value scale at the left side of the graph can be used as scrollers to constrain movement to one axis. Drag the time scale to move back and forth in time, or drag the value scale to move up and down in the value range.
You can scale in both axes, or constrain scaling to either axis:
The Tools menu in the title bar of the Curve Editor is used to control the display of the Curve Browser panel, Keypoint Viewer panel, and Curve Colors palette.
The Curve Browser It lists all animatable parameters for a node. The checkbox next to each parameter is used to control display of the corresponding curve in the graph.
As in the Node Panel, some parameters in the Curve Browser list are grouped under a heading in outline format, which can be expanded to access parameters in the group or collapsed to make more room in the list.
Fig. 8.3 A corresponding curve is displayed in the graph (right) for each parameter you check in the Curve Browser list (left).
The Keypoint Viewer is used to edit keypoints (the keyframe markers on a curve) numerically rather than by dragging them around in the graph. See Editing Keypoints Numerically, which also explains how to enter and edit expressions in this panel.
The Curve Browser and Keypoint Viewer are displayed in the Curve Editor by default. However you can use the Shutter button (located on the inner edge of each panel) to stow either of them out of the way temporarily if you need more room for the graph display.
The Curve Colors palette is used to redefine the colors used to display curves in the graph. A color is assigned to a curve in the order in which the corresponding parameter appears in the Curve Browser list. The first swatch color in the palette is assigned to the first parameter in the list, the second color to the second parameter, and so on.
To change a color, check the Curve Colors item in the Tools menu to access the palette (it is not displayed by default). Right-hold on a swatch in the palette and a color spectrum bar will pop up. Drag the cursor across the spectrum to the color you want and release the mouse button. Any curve that uses that swatch will update to match the new color.
A curve can be animated initially in the Node Panel and refined in the Curve Editor, or you can start in the Curve Editor and create keyframes to animate the curve.
A parameter that has not been animated is displayed in the graph as a dashed line. Its value remains constant across the entire frame range.
An animated curve is displayed as a solid line, with each keyframe represented by a point on the curve called a keypoint.
Fig. 8.4 The rotate curve is not animated; the pivot.x curve is animated with four keypoints to create three separate curve segments.
Every animated curve has a minimum of two keypoints, one at each end. You can add as many keypoints to a curve as necessary, and each section of curve between keypoints is referred to as a curve segment.
You manipulate curves in the graph by adding and deleting keypoints and changing their position and value, as well as by applying interpolation functions to curve segments between keypoints.
To create a keypoint, hold down the Control key while clicking on the curve. You don't have to be precise about where you click; you can always adjust the position (frame number and value) of the point once it has been created.
To select a keypoint, click on it. To select multiple keypoints, drag a bounding box around them, or hold down the Shift key as you click on each of them in turn.
Fig. 8.5 Selected keypoint (solid square) is at frame 48 and has a value 1.024. The unselected keypoint is a hollow square.
To change the position of a keypoint, select and drag it. Drag up or down to adjust the value; drag left or right to move the keypoint to a new frame. All selected points move when you drag. To shift an entire curve without changing its shape, select all keypoints in the curve and then drag any one of the points.
To select all keypoints in a curve, click anywhere on the curve except on a keypoint. (Be sure to drag the entire curve by one of the selected points; you cannot drag by clicking on a line segment.) |
To delete a keypoint, select it and press the Delete key. For a curve with three or more keypoints, deleting the first or last keypoint shortens the curve. For a curve with two keypoints, deleting a keypoint returns the parameter to a non-animated state.
You specify the value of each keypoint on a curve when you create and edit it. Then RAYZ interpolates the values for the frames in between, based on the keypoint values.
Linear interpolation is applied by default, but you can assign other interpolation functions to a curve segment. In this way you can control the rate and degree of change in the parameter value across time:
The following interpolation functions can be selected from the Curve Actions menu and applied to the curve segment under the cursor:
Fig. 8.6 The first two segments of the curve use linear interpolation; the last segment uses a Bezier function (note the handles).
When a Bezier function is applied, the appropriate keypoint in the curve will display handles you can use to adjust the slope and acceleration of the curve:
Once Expression is specified for the interpolation, the Edit Expression command becomes available from the Curve Actions menu. Select it to bring up the Expression Editor panel, which is described in See Using the Expression Editor.
When you delete a keypoint, the curve segments on either side are merged. If a different interpolation function had been applied to each segment, the merged segment will use the function from the segment that had been on the left (the preceding segment in time).
Use the Keypoint Editor to examine and edit the values of keypoints numerically. The Keypoint Viewer panel should displayed by default; if not, you can select it in the Curve Editor Tools menu.
All keypoints for the currently visible curves appear in the Keypoint Editor. Two data entry fields are provided for each keypoint, in which you can type a new value:
If the "expression" interpolation type has been applied to the curve, an additional field will be displayed in the Keypoint Viewer in which you can enter or edit an expression to control the value.
Fig. 8.8 Expression field in Keypoint Viewer.
For more information, see also Appendix C: Using Expressions in RAYZ. Step-by-step procedures are given in the section on Entering Expressions in the Curve Editor.
You can copy any curve to another curve using the Copy and Paste commands in the Curve Actions menu:
When you release the mouse button, the values of the first curve are applied to the second.
You can export a curve (save it in a file on disk) and then import it into any RAYZ project file.
Fig. 8.9 Right-hold anywhere in the graph, except on a curve, to access the popup menu used to save and load curve files.
Curves are exported and imported using the Save Curves and Load Curves commands in the Graph Actions popup menu, which is accessed by right-holding in the graph. (Do not click on a curve, or the Curve Actions menu will pop up instead.)
The Save Curves command saves all curves currently displayed in the Curve Editor graph into a RAYZ curve file. When you choose Save Curves from the Graph Actions menu, a dialog box will appear in which you can name the curve file and specify where to save it.
If you select an existing curve file, the new curve data will be saved to it, replacing the old curve data in the file.
A RAYZ curve file is simply a text file containing a description of the curve attributes. A curve file is given the ".rzc" extension by default when you create it, and the dialog box used to load curves will display all files in a directory with this extension.
You can load not only RAYZ curve files, but Boujou 2D track data and Maya parameter curve data.
To import a curve, choose the Load Curve command (Ctrl-o) from the Graph Actions menu to open the Load Curve dialog box. Select a curve file from the File list in the middle pane. (Navigate the directory structure if necessary to locate the file.)
When you select a curve in the dialog, a menu will appear (on the right) for each curve available in the curve editor graph. Use the menus to specify whether or not the saved curve will be loaded into each curve in the graph.
When a curve file contains data for more than one curve, you can use the Curve Selection menus in the Load Curves dialog box to specify which curve in the file is imported to each curve in the graph. You can
Fig. 8.10 The "curve1.rzc" curve file is selected (middle pane). The Curve Selection menus (right pane) show that a saved curve named "brightness" will be imported into one graph curve, while an "offset" curve is being selected for import to the other.