heterogeneous volumes

[allenh]

Hello! I need to render an image of a volume of various liquids of various densities and compositions mixing together.

My current thinking about the ideal way to solve this problem is with a single volume (as opposed to multiple overlapping volumes), bounded by a nested dialectric (fluid+glass). This volume would contain multiple float3 (or vector, or color) fields, each of which represents the absorption/scatter/phase of the various liquids.

I see that Octane has Volume and Medium shaders that seem complete in terms of providing absorption/scattering/phase parameters (awesome!), and further see that I can input ramps to these shaders, at least for absorption/scattering (which I think gets me pretty close to the ideal case above). It's not exactly clear to me, though, that I can write a few float3 (or color, or vector) fields into a volume that signify the exctinction/scatter values of my various liquids. Might anyone be able to confirm or deny the possibility of this? It needn't be animated for my purposes, but does need to vary throughout the volume (which would, of course, mean my volume is a heterogeneous rather than a homogenous one). I see a few inputs to the volumeRamp/mediumRamp shader nodes, but it's not clear to me what the inputs are meant to be. I see new inputs show up when I create new points on the volumeRamp, but the data type on these new inputs seems to differ from what I expect. And, the documentation on these nodes suggests they are 'static', which confuses me, then, about how they're driven (i.e. what is the index to the ramp)?

Thanks!