SyncKey Reducer Keeps Poses Together

For those who don’t know the tool: AP SyncKey Reducer is an animation cleanup tool by Amir Porat, sold in separate editions for Autodesk 3ds Max and Autodesk Maya. It reduces dense baked or motion-capture animation into synchronised pose frames for subsequent editing.

The keys agree on a meeting

Amir Porat’s AP SyncKey Reducer tackles a specific animation-cleanup problem: reducing a dense bake while keeping the surviving keys aligned across the channels and objects being processed. The result is intended to give animators complete pose frames to edit, rather than a smaller collection of unrelated curve decisions. A tidier timeline is welcome; one that still speaks in poses is more useful.

The developer’s product pages describe two analysis engines with different priorities. Peak Detection looks for changes in the character of the motion, including direction reversals, impacts and easing. Min Error Removal repeatedly removes the candidate whose loss introduces the least deviation. The Maya documentation specifies that it reassesses the progressively reduced keyset after each removal, rather than making every decision against an unchanged list of candidates.

A floor for the pruning shears

The Maya edition adds an explicit Floor control to Min Error Removal. It sets Strength to the greatest reduction that remains within the tool’s stated error limit. Increasing Strength beyond that point produces a PAST FLOOR warning. That is a threshold calculated by the tool, not a guarantee that a performance still reads correctly in the shot camera.

Removal Error and Keep Priority graph views expose the cost and order of removals, with retained frames marked. Once analysis has finished, moving Strength selects frames from cached results without resampling the scene. Porat describes that adjustment as instant, including on heavy rigs; the initial analysis is a separate operation and should not be confused with the responsive slider that follows it.

Propagation provides another safeguard in Min Error mode by retaining additional keys around rotation events. A turn higher in the hierarchy can move everything below it, so a wrist or spine rotation need not disappear merely because an aggressive setting wants fewer keys. The documentation also preserves keys around Euler wraps and switches, which means the final count can exceed the amount suggested by Strength. Sometimes a few extra keys are doing an actual job.

Read the rig before trimming it

Maya’s implementation operates on existing animation keys and documents explicit exclusions. It leaves constraints, driven keys, expressions, motion paths, locked or muted channels, curves inside referenced files, and channels animated on two or more animation layers untouched. The status line reports skipped items. On a channel animated on exactly one layer, it can reduce that layer’s curve.

This makes the choice of objects consequential. Porat advises reducing an IK handle and its keyed controls when they drive a limb, rather than targeting joints whose movement comes from the IK solve. Detecting a referenced rig for batch organisation does not mean the tool will rewrite protected curves inside that referenced file.

The documented switch handling retains keys at IK/FK, space and visibility changes, together with the preceding frame, and keeps both sides of an Euler wrap. Each curve is rewritten only within its own keyed span. These are specific preservation rules; they should not be inflated into universal compatibility with every rig a studio has accumulated since the last pipeline migration.

All Frames is intended for baked and mocap data, while Existing Keys Only thins a hand-keyed shot without shifting keys to new frames. Sync Extra Channels extends the shared retained-frame selection to attributes such as blendShape weights, ikBlend, constraint weights, visibility and custom attributes. Those options remain subject to the edition’s documented eligibility and switch-protection rules.

One rig, several sensible groups

Auto-Create Object Sets in Maya uses joint names and the actual parent chain to build groups for body parts. Batch Mode can then process selected rigs or object sets, with each group becoming its own undo step. This supports a more selective cleanup pass when fingers, limbs and the torso need separate treatment; the entire character need not attend the same reduction committee.

The Max edition lists CAT-rig support, automatic selection sets, saved reduction presets and weighted or independent position/rotation coupling. It also offers adaptive local normalisation for subtle movement. Maya recognises Biped and CAT naming conventions on exported rigs, but its product page explicitly says this does not provide CAT-layer support. A familiar joint name is not a transported feature.

The Maya page distinguishes the processing implementations as well: its Min Error engine is pure Python, while the Max edition has a native accelerator. Long Maya clips with many joints can therefore occupy the host during analysis. A progress display and Esc cancellation are documented, with Peak Detection available as the faster alternative. No cross-host timing benchmark is supplied.

Preview first, accept deliberately

Maya’s A/B and Revert functions restore original animation keys, including tangents and weights. Accept commits a reduction as one undo step, and Revert is documented to retain unrelated work performed during the preview. The edition reduces animation in place and does not provide the Max CAT-layer “keep detail” feature.

Stepped Keys can make the retained poses easier to inspect. Delete All Scale Keys deserves a less casual click: the Maya documentation says it clears scale keys across the whole timeline, not only the selected reduction range. A command can be accurately named and still require reading the rest of the sentence.

https://amirporat.gumroad.com/l/synckey_reducer?layout=profile

Availability:

Both editions are available separately from Porat’s Gumroad store. The Max listing specifies 3ds Max 2022–2027 on Windows 10 or 11 and supplies a drag-and-drop .mzp installer. The Maya listing specifies Maya 2027 on those Windows versions; macOS and Linux are currently unsupported. Its listed v01.05 package installs through an install.py file dragged into the viewport, adding a SyncKey button to the AP_Tools shelf.

The stores displayed €25 per edition, reduced to €20 with code LKUI4WD when checked. No promotion end date was shown, so the discount should be checked again before publication. These are the displayed euro prices; no currency conversion or tax qualification has been added.

Both products use per-user licensing and include bug-fix updates. Maya has its own licence key and specifies one machine at a time, with up to 10 activations over the key’s lifetime. A new machine or Windows reinstall consumes an activation; reinstalling Maya or the tool does not. Its page calls the initial activation a one-time internet requirement but also describes offline operation as a 30-day cache plus a further 30 days of grace. That wording does not establish indefinite disconnected use, so studios needing longer isolation should clarify it with the developer.