BD Export OVoxel

The expensive part of a TRELLIS2 pipeline isn't the bake - it's the voxelgrid generation, which takes minutes of GPU time and a chunk of VRAM. BD Export OVoxel is the node that saves that work so you never have to regenerate it. It writes a TRELLIS2 VOXELGRID to disk in o_voxel's native .vxz compressed format, alongside a .mesh.npz sidecar holding the original high-poly mesh, and BD Load OVoxel picks both back up later for re-baking without the regeneration step.

If you've ever rebuilt a workflow at 2am and waited for texture generation again, you already know why this node exists.

How it works

Your VOXELGRID is a sparse voxel octree (that's the "OVoxel" representation TRELLIS.2 introduced - a field-free sparse-voxel latent). .vxz is o_voxel's native compression for it. The output is two files, and you need both: the .vxz for the voxel data and the .mesh.npz sidecar for the original mesh. Load them together with BD Load OVoxel and you can re-run the bake (BD OVoxel Bake → simplify → UV → albedo/normal/roughness/metallic) as many times as you like without ever touching the generator.

The dials:

• voxelgrid (required) - VOXELGRID from TRELLIS2 texture generation.
• output_dir (mesh_export) - directory name relative to ComfyUI's output/ folder.
• filename (voxelgrid) - base name, no extension.
• compression - zstd (fast, good ratio, recommended default), lzma (smallest files, slowest), or deflate (standard zlib).

Outputs: vxz_path and status. Wire vxz_path into a text node so you know where it landed.

Installing

Part of ComfyUI-BrainDead. ComfyUI Manager → search "BrainDead" → install, or:

cd ComfyUI/custom_nodes
git clone https://github.com/BizaNator/ComfyUI-BrainDead
cd ComfyUI-BrainDead
pip install -r requirements.txt

Restart. One real dependency caveat: this talks to o_voxel at runtime - if the import isn't available the node returns ERROR: o_voxel.io not available. o_voxel comes in with the TRELLIS2 ecosystem (ComfyUI-3D-Pack and friends), so if your TRELLIS2 nodes work, this likely does too - but it's worth knowing the error message means "install o_voxel," not "your pack is broken."

Where people get burned

People save the .vxz and lose the .mesh.npz, then can't reload - keep both files together; that's not a bug, it's the format. And the compression pick is about disk size vs. reload time: for iterating on a bake, zstd is the right call and lzma rarely pays for itself. The intended loop is Export once, Load everywhere.