Troubleshooting

The mesh doesn’t deform when I scrub Progress in the editor

This is expected. The dynamic materials that carry the effect are created when the game starts, so the deformation is play-time only: it shows in PIE / Simulate, not while scrubbing the slider at edit time.

To preview at edit time, use the panel’s Live Preview toggle. To drive it at runtime, use Auto Play or SetProgress(). See Playback & Blueprint.

Live Preview is on but nothing happens

The deformation is only visible once the slot’s deform material exists. Generate first, then preview: on the Meshes & Materials tab, click Generate Deform Materials, then flip Live Preview on.

The moving mesh ghosts or smears

If the mesh leaves a trail under TAA / TSR, its material is missing the motion-vector wiring (the previous-frame parameters and the PreviousFrameSwitch). Materials authored by Generate include this automatically. If you wired a material by hand, see the Material Contract; make sure the SplineJuice_Prev* parameters are present.

The mesh gets culled / clipped while deforming

WPO pushes vertices outside the mesh’s original bounds. Spline Juice auto-expands each mesh’s bounds while deforming and restores them at rest, so this normally just works. If you see clipping with a custom material, confirm the deformation goes through MF_SplineJuiceDeform (which the bounds logic is matched to) rather than a hand-rolled offset.

My Assembly section only shows a “Bake Pieces…” button

Assembly is bake-gated: the controls only appear once the mesh is split into pieces. Click Bake Pieces…, choose a split mode, preview, and Commit. See Assembly Along the Spline.

The piece preview collapses to a single piece

The mesh is welded; the split mode found only one connected shell. Switch to a different split mode (Lattice always shatters any mesh into chunks). The Segmentation preview flags this so you can catch it before committing.

I edited the original material’s graph but the effect didn’t change

The deformation runs through generated variant materials, not your originals. After editing an original’s graph, re-open the panel and choose Recreate from source (not Update) so the variants are rebuilt from the current source. Recreate is destructive to the generated assets only.

Materials warn about missing parameters in the Output Log

The material doesn’t expose the required SplineJuice_* parameters. Either run Generate to author a compliant variant, or, for a custom material, add the missing parameters listed in the warning. See the Material Contract for the full list.

The panel won’t open / buttons are disabled

The settings panel is an edit-time tool. Both entry points disable themselves during Play / Simulate, because they write persistent config and content assets that mustn’t land on a transient play-session actor. Stop the simulation and re-open the panel.

My per-actor spline snapped back to the template shape

It shouldn’t, once you’ve arranged it. A linked template’s Spline Shape is seed-only: it applies to an un-arranged spline, but a viewport point-drag or a Common Centroid aim makes the actor’s spline authoritative. If a shape did get overwritten, it was still un-arranged at the time. See Reusable Templates.