The Curve Editor allows you view and edit animation data as splines or function curves. You can manipulate both the timing and values of keys, as well as insert and delete keys.
The Curve Editor is displayed when you open a new animation panel. You can also show it by clicking the Curve Editor button on the right of the Animation Panel. You can see the Curve Editor and Dope Sheet at the same time by clocking the Split/Unsplit button, also on the right of the Animation Panel.
The Curve Editor is divided into 3 main areas. On the left is the node list, which displays all the animated nodes in the project. To the right is the Curve Editing view, where you can view and edit the animation curves. At the bottom of the panel is the Tool area.
The node list displays all the animated nodes in the project. It's a hierarchic list. At the top level is the name of each animated node. When you expand the top level you will find items for each animated param in the node. For params with multiple coordinates you can then expand the item further to see items for each coordinate.
Double clicking on a node name in the list will open that node in a floating param view. Double clicking on a param item or coordinate item will fit the curve(s) for that item in the Curve Editing view.
Selecting a list item will display, if appropriate, the curves for that item in the Curve Editing view as well as show the keys for that item in the Timeline.
Curve Editing View
The Curve Editing view allows you to view and manipulate animation curves for the item selected in the Node List. No curves are displayed for top level node items. Param items will display all the curves for that param, although the curves are not editable. To edit a curve you need to select a coordinate item. If a param has multiple coordinates then the curve for the selected coordinate is editable. The curves for the other coordinates are displayed for reference purposes but are not editable.
When a displayed curve is editable the keys are shown by little white diamonds. You can select keys by clicking on them or drag selecting. Selected keys are drawn in orange.
If the param doesn't have multiple coordinates then you can edit the curve as is. However if a param has multiple coordinates then the you can't edit the curves when a param item is selected and multiple curves are displayed. You will need to select a single coordinate of the param to edit. See below for more information about editing curves.
The position of the active frame is shown with a green frame cursor that is drawn the whole height of the editing view. You can click and drag the frame cursor to move it around. When the frame cursor is selected it has orange stripes. If the frame cursor is outside the area displayed in the view a little green box is drawn in the top left or right of the view which shows which frame the cursor is positioned on. You can double click that little box to centre the view on the frame cursor. You can also move the cursor into the view using the "Centre frame cursor" key.
The working frame range is shown by the area of the view with a darker background.
The Curve Editing view has a value guide you can use to help you read values on the vertical axis of the view. Use the "Toggle value guide" key to show and hide it. You can click and drag the guide to reposition it. When the guide is outside the view a little green indicator is shown, pointing to the location of guide. If you double click the green indicator the view will centre on the guide. You can also bring the guide into the centre of the view by pressing the "Centre value guide" key.
The editing view can be manipulated in much the same way as the network view. You can pan and zoom it and fit it to the working frame range or the selected curve(s). See below for more about input settings for the editing view.
Directly under the editing view is a scroll bar. The scroll bar only scrolls the view through the working frame range. There are little buttons with double arrow icons at each end of the scroll bar. You can use these buttons to scroll outside the working frame range. Click and hold them to continue scrolling.
The Tool area is at the bottom of the window and contains some controls for manipulating the Curve Editor. These are the controls currently available (STC):
Curve mode popup
This popup lets you choose the interpolation mode for the selected item in the node list. If the selected list item is a param item then changing the curve mode will effect all the coordinates of the param. There are two choices at present - Linear and TCB. These are explained further in the Curve Editing section below. There is also a "Mixed" item which is disabled. This item is selected when the selected list item is a param item and the coordinates of the param don't all use the same interpolation mode. You can't actually set the interpolation mode for an item to "Mixed" yourself.
Fit to working range button
This button will fit the editing view to the current working frame range.
Fit to selected keys button
This button fits the editing view to the selected keys.
Fit to selected curve button
Clicking this button will fit the editing view to the curve(s) selected in the node list.
Move keys button
Press this button to enter the normal selection and movement mode for editing keys.
Scale from frame cursor button
Click this button to scale selected keys from the frame cursor. This scales the frame positions of keys but not the values. Select the keys you want to scale and then drag a key left or right to scale them around the frame cursor position. For example, if you wanted to scale keys from the start of the working frame range you could move the frame cursor to the start. If you wanted to scale the keys around a particular frame then you would first move the frame cursor to that frame. Dragging past the frame cursor will reverse key positions.
Scale from centre of selected keys
Click this button to scale selected keys from the centre of the selected keys. This scales the frame positions of keys but not the values. The centre of the selected keys is the frame position half way between the first key and last key in the selection. As an example if the first key was at frame 1 and the second key was at frame 10 then the keys would be scaled around frame 5.5. Drag one of the selected keys left or right to scale the keys. Dragging past the centre position will reverse key positions.
Scale keys from value guide
Click this button to scale selected keys from the value guide. This will scale the values of the keys but not the frame positions. Select the keys you want to scale and then drag a key up or down to scale them around the value guide position. Dragging past the value guide will reverse key values. Note that this scaling method will work whether the value guide is currently shown or not. You can show the value guide using the Toggle value guide hotkey.
Scale keys from centre of selected values
Click this button to scale the values of the selected keys from the centre of their values. This scales the frame positions of keys but not the values. The centre of the selected keys is the value half way between the first key and last key in the selection. As an example if the first key had a value of 20 and the second key had a value of 40 then the keys would be scaled around the 30 value. Drag one of the selected keys up or down to scale the keys. Dragging past the centre value will flip key values.
Action edit field
You can use this field to enter values for operations performed using the Action button, described below. Note that when you are scaling keys the value in this field is taken to be a percentage. For example to scale keys to twice the length you would enter 200 for 200%.
The Action button pops up a menu which lets you choose from a number of different operations. You can use it to move keys, scale keys by a percentage or to jump to a frame or value. The value used for each operation is taken from the Action edit field. Let's say you want to move the selected keys 4 frames to the right. You could enter 4 in the Action edit field and then choose "Move keys" from the Action button menu. To move the keys to the 4 frames to the left you would enter -4 in the Action edit field.
Animation data is displayed in the Curve Editor as curves or splines connecting key positions. Key positions are shown on the curves by little white diamonds. You can edit the curves by moving, scaling, inserting and deleting keys.
You can control the way the animation data is interpolated. At present there are two methods. Linear interpolation connects keys with straight lines. The values change at a constant rate between keys. Linear interpolation is really a special purpose method. It's not really recommended for general animation, especially motion (unless it's in a straight line) as the sharp angles in the lines around key positions can cause abrupt changes in animation that might not look good.
The other interpolation method is TCB, which uses TCB splines. TCB stands for Tension Continuity Bias, in case you were wondering. TCB splines produce smooth curves which automatically ease in and out around key positions, which produces smoother animation.
Not all curves displayed can be edited. When a param item is selected that has multiple coordinates you cannot edit the curves displayed. You will need to select an individual coordinate (X,Y,Z or Red, Green, Blue) in the Node List before you can edit its curve.
Keys can be selected by clicking on them or by drag selecting. You can select multiple keys. When keys are selected you can move them around by clicking on a selected key and dragging it. Key positions snap to whole frames as you move keys. Fractional frames are not supported yet.
When you move one key past another one the key being moved will be repositioned on the appropriate side of the key which is being moved past. This prevents loops and undercuts being formed in the spline.
You can insert a key by pressing the I key and clicking in the editing view where you want the key to be positioned. You can also use the view context menu to add keys at the mouse location.
You can delete keys by selecting them and pressing the delete key. If you delete all the keys for a param it will be removed from the Node List. You will need to set a key on it again to see it back in the Node List for editing.
If you want to move or scale keys by a certain amount you can use the Action button. First enter the desired amount in the Action edit field and then choose an operation from the menu that pops up when you click the Action button. Note that the amount in the Action edit field is interpreted as a percentage when you choose a scale operation.
The Action button can make it easy to flip or reverse keys. First select the keys and then enter -100 in the Action edit field. Next select the appropriate scale operation from the Action menu. The scale factor of -100 will reverse the keys without otherwise changing their timing.
At the moment you cannot edit the tangents or ease-in or ease-out of the splines. You may need to insert or delete keys to get the desired curve.
These are the input and manipulation methods available for the editing view. See the Mouse and Key Settings dialog for the input bindings.
Zoom - zoom the view
Zoom frames in/out - zooms the view horizontally
Zoom values in/out- zooms the view vertically
Windowed zoom - click and drag to zoom in on a specific part of the view
Pan, up/down/left/right - pan or scroll around the view
Fit to working range - fits the view horizontally to the current frame working range
Fit to selected keys - fits the view to the selected keys
Fit to curve - fits the view to show all of the curves selected in the Node list
Reset to origin - repositions the view to the origin (frame 0, value 0)
Centre frame cursor in view - this will bring the frame cursor into the centre of the view
Centre value guide in view - this brings the value guide into the centre of the view
Toggle value guide - this toggles the display of the value guide
Insert key - this activates the insert mode and a new key will be inserted in the curve when you click in the editing view
Delete key - deletes the selected keys
Nudge up - nudges the selected key up
Nudge down - nudges the selected key down
Nudge left - nudges the selected item (key or frame cursor) left by one frame
Nudge right - nudges the selected item (key or frame cursor) right by one frame
Switch to X/Y/Z/R/G/B component - switches the component being edited. For example if you are editing the Y component of a param and want to change to the X component you can press the X hotkey instead of having to select the X component from the Node list.
Advance to next component - this advances through the editable components of a param. As an example, if you are editing the Y component and press the hotkey the view will switch to editing the Z component.
The Node List is a part of the Terragen interface that shows a list of nodes along the left side of the application window. The Node List generally shows only those nodes that are relevant to the current Layout (e.g. Terrain, Atmosphere). It sometimes includes buttons or other controls that are specific to a particular Layout as well. The Node List is hierarchical and each level is collapsible.
A single object or device in the node network which generates or modifies data and may accept input data or create output data or both, depending on its function. Nodes usually have their own settings which control the data they create or how they modify data passing through them. Nodes are connected together in a network to perform work in a network-based user interface. In Terragen 2 nodes are connected together to describe a scene.