Project 2d texture into volume along surface normal

[Dan Andersen]

Hello,

I often use the VrayEnvironmentFog volume bounded to geometry and usually plug in 3d textures and VRayDistanceTex nodes to control its appearance in a volumetric way. This is great for shading ice, clouds and many other things.

The current workflow is quite flexible but one thing that could open up a lot of new possibilities would be the ability to project a regular UV mapped 2d texture into the volume. It should be in a way that corresponds to the placement on the surface, so my idea is to have a node that can project a 2d texture along the (negative) normal of the surface, 'into' the volume.

Any thoughts?

Cheers,
Dan

[vfx_film_televsion]

where do you plug in the vraydistancetex node, and what does it control ? just interested because I do something similar but without this node :O

kind regards
pirmin

[vlado]

The current workflow is quite flexible but one thing that could open up a lot of new possibilities would be the ability to project a regular UV mapped 2d texture into the volume. It should be in a way that corresponds to the placement on the surface, so my idea is to have a node that can project a 2d texture along the (negative) normal of the surface, 'into' the volume.

The only possible thing would be to get you the UVW coordinates of the closest point on the object's surface; the distance texture computes the closest point anyways, so it shouldn't be slower. Will need to think how to wire this in the UI though.

Best regards,
Vlado

[Dan Andersen]

where do you plug in the vraydistancetex node, and what does it control ?

It has a lot of uses.

You can either link the distanceTex node to the geometry being shaded as a volume itself, to create different volumetric falloff effects from the surface (say driving the vCoord of a ramp to change color based on the distance from the surface, or connected to the threshold of an inverted 3d noise to break up the volume outline (great for cloud and smoke effects)).

Or you could link the distanceTex to other geometries for emitting 'light' inside the volume (and you can remap the distance any way you want, so you can create falloffs that you can't do with regular lights) or adding/subtracting density in interesting ways.

[Dan Andersen]

The only possible thing would be to get you the UVW coordinates of the closest point on the object's surface; the distance texture computes the closest point anyways, so it shouldn't be slower. Will need to think how to wire this in the UI though.

Best regards,
Vlado

This could be very cool. Could a UI option be to add a checkbox to the VRayEnvironmentFog called 'project surface textures' (or something like that) + a 'projection depth' float for the distance, that, when enabled, would apply this to any 2d textures connected to the volume (I know this means we wouldn't be able to reuse any closest point calculations done by distance nodes in the network)? #edit <-- I guess this wouldn't be ideal in that you would only have a single distance per volume, so if there were multiple textures being projected, we couldn't set the distance per texture.

Alternatively have the 'project surface textures on volumes' attribute on the VrayDistanceTex node?

[vlado]

I was rather thinking to have options for the various VRayDistanceTex slots to evaluate the respective texture at the closest point on the surface of the "distance" mesh? It seems to me the most flexible approach. We could also potentially map the W coordinate with the distance itself, so you could get something like a 3D volumetric texture layer along the surface of the distance mesh...

Best regards,
Vlado

[Dan Andersen]

This sounds perfect and has even more uses than I initially thought of. If this makes it into VRay, I'll be all over it

[Dan Andersen]

We have a project starting up next month, where we'll be doing some shots with cracked ice where this could come in handy for the cracks. In the past I've always brute-forced this with actual geometry for cracks, but would love to see how far this 'volumetric texture layer along the surface of the distance mesh' could go. It could potentially offer a lot more detail and flexibility + the ability to easily animate the cracking. Any chance for a rough implementation of this?

[Dan Andersen]

*bump*

This could still be the coolest thing ever - texture transfer via VRayDistanceTex - any news?

[yolov]

I just double-checked with our developers and this is currently in progress. It will, however, be part of V-Ray Next.

[Dan Andersen]

I somehow managed to miss your reply back in May, Alex - just seen it now. Nice!

[Dan Andersen]

Just checking in. Is this still in progress?

[Dan Andersen]

I just double-checked with our developers and this is currently in progress. It will, however, be part of V-Ray Next.

I don't think this ever made it into Next. Crossing my fingers for seeing this in VRay 5..(?)