3D
Gaussian splats and VDB volumes
JOS reads and renders both itself, with no extra software. Both are composited by depth with the Hydra render (in front of, among or behind the scene's surfaces) in RenderScene and in the 3D viewport.
ReadSplat and ReadVDB are objects like the others: plug them into a Scene, and place them with their own translate, rotate, scale and pivot (or by moving them in the 3D view).
Gaussian splats
ReadSplat reads:
.ply: the usual 3D Gaussian Splatting training output, binary or text, any spherical-harmonics degree;.spz: versions 1 to 3;.splat.
Dropping one of these files on the graph makes a ReadSplat.
Settings: - colorspace: the splats' colour encoding. Empty means sRGB. - holdout: the splats hide what's behind them but add nothing.
How they render: - With Edit > Preferences > Performance > Process on the GPU with Vulkan on (the default), splats render on the GPU. A million splats take a few tens of milliseconds at HD. Otherwise they render on the CPU. - Where splats cover at least half a pixel, RenderScene's depth, position, normal and Cryptomatte passes are theirs. - Their colours are converted to your working space through OpenColorIO.
Tips: - To place splats, select them in the viewport and move them: the ReadSplat's transform settings follow. - Captures from COLMAP usually come in upside down: set the ReadSplat's rotate x to 180.
Not yet: SuperSplat's compressed .ply, animated splats in a USD stage, deep output.
VDB volumes
ReadVDB reads a .vdb file or a sequence (smoke.####.vdb). Dropping one on the graph makes a ReadVDB.
| Knob | Default | What it does |
|---|---|---|
| frame offset | 0 | Shifts the sequence in time |
| density grid | density |
The grid that holds the smoke |
| density_scale | 1 | Thicker or thinner smoke |
| color | 0.8 grey | Albedo of the smoke |
| anisotropy | 0 | Forward (+) or backward (−) scattering |
| shadows | on | Self-shadowing |
| emission | auto | The grid that glows: auto finds flames, fire, heat or temperature; or none |
| emission_intensity, emission_scale | 1, 1 | Brightness of the glow |
| ramp from / to (K) | 1000 / 2500 | Blackbody colour range for the emission |
| step | 0.5 | Ray-march step in voxels: smaller is finer and slower |
| holdout | off | The volume hides what's behind it but adds nothing |
Lighting: - Volumes are lit by your Light3Ds and by the stage's own lights. With no light at all, a key light from above and behind the camera is used. - In RenderScene, volumes and surfaces cast shadows on each other, and volumes shadow each other.
Grids: float, double and half scalar grids, uncompressed, zip or Blosc. Volumes inside a USD stage render too. The emission colour is converted to your working space.
Not yet: vector grids, velocity motion blur, GPU rendering of volumes, volumes in Storm's own preview, deep output.