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Pose-to-pose animation
This involves keying the important poses where they occur in time, then filling in the tweens. This is the common method for doing 3D computer-based animation.
This is a newer style of animation, dating from the 1960s: the master animator would create main cells (two or three per shot), additional cells (between 5 and 10) would be filled in "from storybook", and then the remaining in-between cells would be created.
This style involves two phases:
Blocking
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Lay out the rough animation by creating the important poses where they occur on the timeline.
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Set keyframes on everything that’s key-able. This is for control and predictability: you don’t want to accidentally leave something un-keyed. This is also much faster than selecting the parameters to key.
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Use constant (straight) or sometimes linear transitions between keyframes in the animation editor . This makes the character jump between poses.
Keying everything gives quick, immediate results, but it can become difficult to tweak the animation later, especially for complex characters.
To set up Houdini for blocking:
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Choose Edit ▸ Preferences ▸ Animation and set Global set key to Set keys on all scoped channels.
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Turn off Autokey: Add keyframes on parameter change.
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Create a channel group containing the parameters of the character’s world space controller Nulls. Use the channel group to scope the parameters to keyframe.
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Copy the current pose to create the next one: pose the character, key everything, then copy the keyframe in the playbar to another frame, and key everything at that frame. See how to edit keys on the playbar .
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Use flipbook blocking to move the blocked poses around in time.
Posing
In this phase, you clean up the animation by deleting unused animation (delete keys on straight curve segments) and set up transitions between keyframes (convert constant transitions to ease, constant, or spline).
As the characters transition between the main poses, you add keyframes for finer controls, keying only the affected parameters.
A good workflow for this phase is to work on the hips down to the feet on the first pass, and the neck down to the arms on the second pass.
In this phase you will often run into a series of diminishing returns for tweaking the character. After much tweaking, making small changes begins to take a lot of effort.
Straight-ahead animation
This involves posing the character for every second ("on 2s"), third ("on 3s"), or fourth ("on 4s") frame on the first pass, then doing "clean-up" passes to fill in additional poses where needed.
This is a kind of performance-based animation, similar to how one animates in traditional 2D cel animation. This technique is considered fairly advanced; few CG animators work this way. It requires planning ahead, acting ability, understanding of the character, and experience.
To set up Houdini for straight-up animation:
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Choose Edit ▸ Preferences ▸ Animation and set Global set key to Set keys on all scoped channels.
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Turn off Autokey: Add keyframes on parameter change (because you're tweaking and keying everything anyway).
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You don’t need to use the animation editor (because you don’t need to control tween functions), you can use the "Pose" pane layout as-is.
You can even hide the take list and parameter editor until you're done the first pass.
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You don’t need to create channel groups until the clean-up passes.
