trying to get CustomRenderTexture volumes working in VSeeFace and am raymarching through the voxel data, though it only seems to render CRTs on load.

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For drawing the cut part, just ignore the raymarching anywhere where the first ray distance < 0, since that means it's already inside the surface.
For clipping the result to a sphere, just get the distance of the final ray position to the origin and mask out anything > sp. radius

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