Rendertimes with VrayDistanceTex

[ben_hamburg]

Hi there,

I have a problem with rendertimes on the following setup:

I have an object with a composite map in the diffuse channel. This Map has a VrayDistanceTex map as a mask, which has three animated objects as Distance objects.
So far so good.
But that object also has a Vraydisplacement modifier on top and the displacement map is a monochrome version of the Diffusemap.
And as soon as I enable the displacement modifier, render times are going through the roof.

I guess it has something to do with the Vraydisplacement beeing taken into consideration for the calculations made by the VrayDistanceTex map or something like that, which is something I don´t really need actually.

Therefore my question would be: Can I somehow use a dummy object without vraydisplacement and use the VrayDistanceTex on that one, but use the output to drive the displacement of the main object?

[ben_hamburg]

Haven´t figured out a solution yet, but at least I was able to speed up the process somewhat by changing the geometry type to static in the Vraydisplacement modifier...

[joconnell]

I could be wrong but I think it might be the composite map? A lot of the autodesk engineers themselves had mentioned that it isn't that quick. Would if be possible to try a different method to achieve the same thing like use a mix map or a vray comptex instead? If you were to just use the distance tex in the diffuse channel and displacementmod, while it gets you the wrong look, does it solve the speed issue thus pointing to the composite map?

[ben_hamburg]

If I disable the Vraydisplacement modifier rendertimes are back to normal, that´s why I figured it had to be that part slowing it down and not the compositemap, but still a good idea to give that a try...

[svetlozar.draganov]

Another approach would be to make two versions of the displaced-objects. One for the rendering and another one non-renderable without displacement for controlling the DistanceTex.

[ben_hamburg]

Another approach would be to make two versions of the displaced-objects. One for the rendering and another one non-renderable without displacement for controlling the DistanceTex.

That was my first idea...Doesn´t seem to work though...Since the Distance-Map is applied to the renderable object aswell, it still uses it´s geometry to calculate the distance values.
Haven´t found a workaround yet and as it is I can´t use vraydisplacement and distance tex on the same object, since i can´t afford rendertimes of 3 hours per frame...

Any ideas on how to work around this issue or how to bake the texture information from the vraydistance tex?

[svetlozar.draganov]

You bake VrayDistanceTex map by first plugging it into VrayLightMtl, apply this material to the object in the scene and use standard baking technique to bake VrayCompleteMap of this object. It would be also a good idea to send us a sample scene with this setup for investigation - we might find a way to workaround the issue.

[ben_hamburg]

Ah, ok. I actually never had the need to bake anything, so that solution didn´t even occur to me...I´ll give it a try as soon as possible and I´ll also try to upload a stripped scene for investigation.
Right now I´m in the middle of the production so I had to resort to "oldschool" techniques using volume select and standard displacement modifier.

Since this is something I need quite often for medical animations, I´ll hope to find a good solution for this. If baking works, great, but of course it would be even better if you could find another workaround...

[svetlozar.draganov]

We will try to find another way to workaround it but we will need a scene in order to work on the same setup.