Known limitations

These limitations apply to MotionAtelier 0.4.2.

Platform

• Windows only. Linux and macOS are not tested or supported.
• Houdini 20.0 is untested. It shares Python and Qt with the tested 20.5 builds. See Supported Houdini versions.
• Graphical Houdini only. The panel reads selections from the Channel Editor and playbar UI.
• English only.

Reading keys

• Get Keys reads one channel. With several channels selected, the first valid one in path order is read. Commit Keys applies to all of them.
• Selection order is not known. Houdini does not report the order in which channels were selected, so MotionAtelier always uses path order.
• Disagreeing Channel Editors. If several Channel Editors hold different selections and none is under the pointer, the playbar selection is used instead.
• Non-Bezier segments are read with flat tangents.

Shapes and committing

• Holds cannot be shaped. A curve maps between two different key values. Between two keys with the same value the interval is written flat, so Wave and Noise cannot add motion to a hold. To add variation to motion of any shape, use the Noise, Jiggle or Spring effects on a range that changes value.
• No control for the commit fit tolerance. When sampled effects are committed, the result is fitted within a fixed 0.5 % of the value range. If no fit exists, the commit is refused. The value is stored as fit_tolerance_pct (0.05–10) in settings.json, but editing that file is not a documented workflow.
• Elastic Damping stops at 0.70, where the overshoot is already under 5 %. Use Ease or a Spring effect for gentler settles.
• Wave uses at most 240 keys per interval.
• Handles cannot reach the full segment length, because Houdini cannot store them.
• Keys closer than 0.01 frame count as a collision and the channel is skipped.
• Automatic tangents facing outward on boundary keys are fixed to their current values when committing.

Panel

• No zoom or pan in the graph. The view frames the curve automatically; press F to re-frame.
• Generated shapes cannot be edited by hand until converted with Convert to Ease. After converting, the generator parameters no longer apply to the Ease copy.
• The preview runs in the panel only. It does not move the Houdini playhead or play the scene, and its duration is not remembered.
• History restores the committed curve only, as an Ease curve, not generator parameters or Motion Stack layers. Save a recipe to keep those.
• Recipes, history and settings are per Houdini version. Use export and import to move recipes.

Key Tools

• Scale Keys pivots are per channel. The tooltip of Time Pivot says First Key, Center and Last Key “span every selected channel”, but the shipped code takes them from each channel’s own selected range. Use Playhead for one shared pivot. This difference was found by reading the source and has not been confirmed in Houdini.
• Reduce Keys works on Bezier and linear segments only.
• Preserve Extrema in Reduce Keys is always on.