On this page 
The graph view lets you view and edit animated parameters as graphs of their values over time. It is one view of the animation editor. You can also use the table view and the dopesheet view to edit animation. To switch between these views, use the buttons in the top left corner of the pane.
A channel contains a series of segments. Each segment has two end points. Each endpoint is at a key and has the following properties: value, slope, and acceleration. The segment as a whole also has a segment function associated with it and, depending on what it is, will use any number of the properties at the end points. For example, the constant() segment function uses the "value" of the first end point only, while the bezier segment function uses all three (slope, acceleration, and value) at each end.
Navigation
Adding and deleting keys
To...  Do this 

Add a key 

Remove a key 

Editing curves
The following illustration shows the handles at each keyframe. The handles correspond to the text boxes at the bottom of the graph (Value, Frame, Slope, and Accel), allowing you to set them to exact numbers. (Some indicators may only appear on the selected key.)
You can select a segment and choose the "segment function" to control how Houdini connects the two ends of the segment.
You can use automatic or manual control of slope, and tie or untie value, slope, and/or acceleration at each keyframe.
To...  Do this 

Change the shape of a graph segment 

Move a keyframe in time 
Drag the short vertical line that runs through a value handle left or right to move the keyframe. Time values on the graph have a dashed line under them. When you turn on the Snap to Frame option, keys will move to the nearest frame time when you finish dragging. 
Quickly edit curve slopes 
Select a keyframe and press 0 to zero the slope, or 9 to make the slope tangent. 
"Hold" a value 
Select the keyframe and use Alt + C or ⌃ Ctrl + C to copy it, move along the timeline, and use Alt + P or ⌃ Ctrl + P to paste a copy of it. 
Change a value at a keyframe 
Drag a keyframe handle up or down. Click a keyframe handle and enter an exact number in the Value field below the graph and press Enter. 
Change multiple values at once 
Use ⇧ Shift + to select multiple handles, or drag a marquee around the handles you want to select. The you can drag one selected handle to move them all. If you select more than one value, the Value field shows 
Move a key in X and Y and the same time 
Hold ⌃ Ctrl and drag the value handle. 
Only affect the acceleration and keep the slope orientation intact 
Hold ⌃ Ctrl and drag the acceleration handle. 
Select all of the same type of handles on a channel 
Doubleclick the handle. 
Add all of the same type of handles to the existing selection 
⇧ Shift doubleclick the handle. Note ⌃ Ctrl + ⇧ Shift doubleclick will remove of the same type of handles from the selection. 
Add handles to a box selection 
Hold ⇧ Shift and drag . Note ⌃ Ctrl + ⇧ Shift and drag will remove handles. 
Gear menu
Channels menu
Edit menu
View menu
Snapshots menu
Time Group menu
A time group is a collection of keys. A time group makes it easy to move keys through time together.
To...  Do this 

Group keys together in a time group 

Add keys to an existing time group 

Move the keys in a time group together 

Move the time group line without moving the keys 

Delete a time group 

Settings menu
Edit fields
Frame
The frame number of the selected key or time group. If more than
one key or time group is selected, the field displays 
, and
editing the field sets the value for all selected keys.
Value
The numeric representation of the selected key’s in or out value.
Slope
Tip
You can do simple addition, multiplication, and division on the current value of the field. Replace the current value with, for example:
+ 1.25
…and press Enter. Use *
for multiplication and /
for division. To subtract, add a negative number, for example:
+ 0.5
Function field
A segment’s function controls how Houdini interpolates between keyframes.
Choose a function from the popup menu at the right end of the text box, or type an expression function directly in the text box.
Function  Effect 

Uses the in value for the entire segment, and jumps to the out value at the end. 

Generates a straight line between the in and out values, animating the value with uniform speed along the segment. 

Generates motion that gently accelerates the value at the beginning of the segment and decelerates it at the end. The value starts the animation at rest and ends at rest. 

Generates motion that gently accelerates the value from rest at the beginning of the segment and continues accelerating until the end. 

Generates motion that gently decelerates the value to rest at the end of the segment. 


These are fundamentally the same as the ease functions, but are raised to the power 2, resulting in steeper slopes. You can manually change the power in the Function text box (for example, to 3, 4, 5, etc.) to further steepen the curve. 
Makes the slope of the out curve equal to the slope of the in curve. In the example above, the segment to the right of the key used a Cubic interpolation function. After selecting it and altering its interpolation type to Match, its slope adjusted to match the slope of the curve segment to the left of the key. 

See the expression reference pages for these functions. 

Gives you control over the in and out slopes. 

Gives you control over the in and out slope and acceleration. 

Like the bezier function, but uses a higherorder curve. 



Generates a spherical linear interpolation in quaternion space between the in and out values. This is the default for rotation channels. This function is intended for rotation channels. Make
sure all three rotation channels use Segments with quaternion interpolation will display as
straight lines in the graph editor, because their
intermediate values expressed as euler angles are mostly
meaningless. If you're curious you can use the
expression To perform a quaternion based interpolation between two
key frames, the 
