Troubleshooting

Troubleshooting & Known Issues

Quick fixes for the things people hit first, then the current limitations.

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Nothing happens / no effect at all

• Is the Deformer Graph plugin enabled? TensionFX can't run without it. Edit → Plugins → search Deformer Graph → enable → restart. See Installation & Setup.
• Did you set the Default Mesh Deformer? Open the skeletal mesh, search deform in Details, set the matching DG_TensionFX_* graph. See Use it on your own mesh.
• Want to confirm the vertex colors are there? Two quick ways:
  1. Enable the viewport's Vertex Colors show-flag (View Mode → Vertex Colors) and select the mesh — you'll see the raw red/green stretch/squash directly. (On MetaHumans, see the note below.)
  2. Create or reuse a Material Instance of M_TensionDebug and assign it — it pipes the vertex color straight to emissive.
• Does your material read the right channel? It needs a Vertex Color node feeding your effect — R/G for standard meshes, R (stretch) / Alpha (squash) for MetaHumans.

The effect updates live in the level viewport — you don't have to be in PIE.

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The Material Editor preview looks wrong

The material is fine — the Material Editor's preview mesh just has every vertex-color channel set to 1 (full white), so every stretch and squash effect fires at once and it reads as blown-out. Judge the look on your actual animating mesh in the level instead.

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MetaHuman: I enabled it but the skin doesn't update

The first time you enable TensionFX on a fresh project, the MetaHuman skin material instance sometimes doesn't recompute right away. Force a refresh by toggling any shader-affecting setting once (e.g. flip Use Animated Maps, or toggle Micro Skin Details off and back on). The effect was working the whole time; the MI just wasn't redrawing. This is a one-time hiccup on first setup.

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MetaHuman: the Vertex Colors view looks different from the sqworm

When you inspect a MetaHuman with the Vertex Colors show-flag, it won't show the bold red/green you get on the sqworm: stretch is in Red, but squash lives in Alpha, which that view doesn't display the same way as Green. That's expected — judge the result by the shaded roughness/color response while the mesh animates.

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MetaHuman: a seam appears under heavy stretch

A current limitation, and it's about geometry, not shading: the head and body are separate skeletal meshes, and TensionFX measures stretch within a single mesh — it can't measure across the gap between them. So under strong stretch the two sides can compute slightly different values at the neck and reveal a faint line. To minimize it, keep the head and body skin material settings as similar as possible so both sides react the same way across the seam.

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Current limitations / roadmap notes

These are known gaps in the current version, called out so you're not surprised:

• Seams under extreme stretch (MetaHuman) — see above.
• The sqworm example material is intentionally simple — it doesn't use the modern reroute-node setup that the MetaHuman skin functions do. It's a starting point to customize. (Use M_TensionDebug to inspect the raw vertex colors.)

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Still stuck?

Re-open the Examples level — if the bundled examples work and your mesh doesn't, the difference is almost always (a) the Default Mesh Deformer isn't set, or (b) your material isn't reading the right vertex-color channel.

Send me a DM somewhere!