3d textures possible? (cg sampler3D type)

Is it possible to create 3d textures in unity somehow? Or just import them as assets and use them in cg?

Guess you could try exporting your 3D texture to dds format, though there appears to be some confusion as to what Unity supports with regard to dds.

As to how, nVidia have a number of tools, one of which is dds file support for Photoshop, which although supports volume textures, the documentation doesn't actually tell you how to make them. Maybe its as simple as using multiple layers?

If that fails then there are many other tools from nVidia, so might be worth checking them out.

However my first step would be to source a 3d dds from someone online and test that in Unity to check that it can be used.

edit: according to old forum threads the expected format is

The plugin used to want a horizontal image containing each slice side-by-side, arranged left to right, top slice to bottom slice.

Edit2: I'm also wondering whether

a. You could provide a 2D texture in Unity, but let it be treated as 3D? I'm assuming here that you can layout the 2D texture to match the expected format that 3D texture would follow, though you'll be restricted to non-compressed formats. Depends if a 3d texture in memory is simply one slice after another, then perhaps a vertical 2d texture say 32x1024 would be 32x32x32 3d texture. Thought this is a long shot

b. Doesn't Unity have some linkage to opengl? Perhaps you could lever that to create the 3d texture?

I'm not sure how to load them in Unity, but the Photoshop plugin from NVidia does not seem to create volume textures - at least not correctly - at least not as far as I've been able to tell.

Try using the DirectX texture tool - it is part of the DirectX SDK. Google can show you the download link.