Z Sorting for Volume Previews

[Joelaff]

We are doing a project that involves having live action plates on planes in 3d space. These planes then get moved through volumes created with Phoenix. The idea in the render is that we get the feeling of moving through the volume. This works well.

I wish we could get this effect with the triangle preview mode, where the triangles would be properly Z sorted with other geometry. I get this would be slower, and possibly it would just be too slow to be useful, but perhaps at high reduction levels it might work nicely.

Currently the entire volume gets drawn on top of the other geometry. Or perhaps it is sorted by pivot point it center or something.

Imagine someone standing knee deep in a pool of dry ice fog. I’d like to be able to see where in depth I am positioning the actor on a plane.

[Joelaff]

Hmmm. Perhaps in High Quality mode this is actually working already. I was in Standard mode, which I think just does a basic Z sort.

Good job!

[Svetlin.Nikolov]

Hmmm, I don't think it should work in either mode. Gotta see if there is a nice way of making per-fragment z-depth work with the rest of the viewport the way we have the viewport gpu preview implemented right now, or if we need to do it in a completely new way. I see Maya fluids do seem to blend properly with scene geometry in the Maya viewport, so there IS a way...

[Joelaff]

I am pretty sure I am seeing a basic sort (per triangle in the triangle preview) between a transparent plane (texture mapped with an opacity map) and the triangle preview. I went to high quality, and then I re-selected Realistic Materials with Maps.

However, sometimes that inverts the opacity map for some reason.

[Svetlin.Nikolov]

Ah, the triangle preview should fit with the other viewport primitives pretty well. I was thinking about the gpu preview...

[Joelaff]

Ah, the triangle preview should fit with the other viewport primitives pretty well. I was thinking about the gpu preview...

Ah, OK. Yeah, the GPU preview with Z sorting and hit detection would be awesome, but short of some awesome algorithm innovation we may be a few years away from that hardware-wise.

Who knows, you may have some realization and will will all be doing "Nikolov Hit Detection" next year!