Houdini VAT 3.0 import

Houdini support in EQ VAT Lab is import-only. Artists bake VAT in Houdini, then EQVAT imports the exported mesh, textures, and .mat companion data and wires EQVAT URP shaders. The workflow no longer requires SideFX/VAT_* shadergraphs.

Quick start

1. Open Tools > EQLabs > EQ VAT Lab > Open Editor.
2. Go to the Import Wizard tab.
3. Assign the Houdini export folder to Houdini Folder.
4. Click Auto-Detect VAT 3.
5. Check that Type, Base Mesh, textures, bounds, FPS, frame count, and playback values were filled.
6. Click Validate and then Auto-Fix Textures if texture import settings need repair.
7. Click Import & Generate.
8. Use the generated prefab or open the Preview tab to scrub/play the result.

The same wizard imports EQLabs-native bakes; these stills show one, a Vertex bake read back from EXR textures.

Validate catches the texture import settings that would corrupt VAT data.

Import & Generate: a material, metadata and a prefab that plays.

The Preview tab: scrub the animation frame by frame.

The Preview tab showing the VAT texture itself: every vertex, every frame, in one image.

Supported Houdini VAT 3 modes

Mode	EQVAT shader	Required textures	Optional textures
Soft Body	EQVAT/URP/SoftBody	Position, Rotation	Color
Rigid Body	EQVAT/URP/RigidBody	Position, Rotation	Color
Fluid / Dynamic Remesh	EQVAT/URP/Fluid	Position, LookupTable	Rotation, Color
Particle Sprites	EQVAT/URP/Sprites	Position	Color

The Import Wizard can still be filled manually if auto-detect cannot infer the export layout. Select one of the Houdini VAT 3 Import types, assign the base mesh and required textures, then pull bounds from the mesh or type the values from the Houdini .mat file.

.mat companion data

The parser reads the Houdini/Unity material companion text when present. It looks for:

• Bounds: _boundMinX/Y/Z, _boundMaxX/Y/Z, or _VAT_LocalBoundsMin/Max.
• Playback: _frameCount, _houdiniFPS, _displayFrame, _playbackSpeed, _B_autoPlayback.
• Texture references: _posTexture, _rotTexture, _lookupTable, _colTexture, _spareColTexture, _posTexture2.
• Mode hints from shader/material names such as SoftBody, RigidBody, DynamicRemeshing, Fluid, Sprite, or ParticleSprites.

EQVAT converts those values into the EQVAT shader property layout:

• _VAT_Position
• _VAT_Rotation
• _VAT_LookupTable
• _VAT_SpriteColor
• _VAT_LocalBoundsMin
• _VAT_LocalBoundsMax
• _VAT_HoudiniFPS
• _VAT_DisplayFrame
• _VAT_Speed

Texture import settings

VAT data textures should be point-sampled, linear, mip-free, and uncompressed. Houdini exports commonly use Repeat wrap mode; EQVAT validation accepts Clamp or Repeat and flags mirror modes because they corrupt table lookups.

Use Auto-Fix Textures after auto-detect if Unity imported the textures with sRGB, mips, compression, or a bad wrap mode.

Important limits

• VAT 3.0 is the target. VAT 2.0 / Built-in pipeline Houdini exports are not a production path.
• Optional high-precision Position2 and SpareColor textures are parsed for reporting/future parity, but only the texture slots exposed by the current EQVAT shaders are wired.
• Baking Houdini VAT inside Unity is not part of the EQVAT Baker tab. Houdini remains the DCC baker.

Troubleshooting

Symptom	Likely cause	Fix
Auto-detect finds no type	Folder or asset names do not contain recognizable mode hints	Pick a Houdini VAT 3 Import type manually
Mesh collapses near origin	Bounds metadata was not read or pulled	Assign the .mat companion or click Pull Bounds From Mesh
Animation is static	Frame count/FPS/display-frame values are wrong	Check _frameCount, _houdiniFPS, Auto Playback, and Display Frame
Fluid tears or scrambles	Lookup table missing or filtered	Assign LookupTable, set Filter = Point, disable mips
Looks blurred/smeared	Texture import settings are wrong	Run Auto-Fix Textures