CoronaVolumeMtl + Opacity

[3dboomerang]

Hi,

Can someone comfirm that cutout opacity maps (for example leafs) aren't respected within the CoronaVolumeMtl?

The leaf geometry is respected, but not the opacity. Rather annoying if it's true, cause I'd have to use high-res trees with leafs being the geometry.

[TomG]

Not sure what you are trying to do here, the CoronaVolumeMtl wouldn't be a good fit for leaves in any situation I can think of.

Are you trying to set up a cube, and then have a 3D material that makes leaves appear inside it? If so, that would not be possible - bitmaps only have 2D information and not 3D information, so there would be no bitmap that could "scatter" the leaves through the volume (you'd have just one leaf texture, projected planar throughout the material).

If you are just trying to texture a single leaf, CoronaVolumeMtl would not be the right choice (it has no surface for reflections etc.) and a regular CoronaMtl with translucency would be the way to go, or SSS there if you felt like it.

Anyway, let us know more about what you have in mind here, as I am not clear on that :)

[pokoy]

I think OP is talking about volume shadowing not taking into account opacity mapping on geometry but only the geometry 'outlines' instead.
But it works here, tested with both procedural and bitmaps for opacity... and with both VolumeMtl on a box vs global volume. So maybe I'm misunderstanding this, too.

OP, the only thing to keep in mind is making sure that if you're using VolumeMtl on a box (or geometry in general) you need to make sure the camera is outside of that box. Otherwise there will be no volumetric effect at all. Or use the global volume slot in the Corona's Scene tab, that'll work regardless of the camera.

[TomG]

Ahh, so it isn't using the VolumeMtl ON the leaf, but how a plane with an opacity map casts shadows through a VolumeMtl, that makes more sense :) I'll take a look at how that is working for me.

[TomG]

If that was the question, it is working for me, both for a cube with VolumeMtl applied, with leaf inside and outside of the cube, in "Inside Volume" and "On Surface" mode; and also working with a Global Env VolumeMtl too.

This was using one CoronaBitmap JPG into diffuse, and one CoronaBitmap black and white JPG into Opacity with Clip enabled, in case it's relevant.

[3dboomerang]

It didnt work for me, let me try to reproduce today and post

grts