V-Ray 5 mapping C4D Noise incorrectly inside materials

[JeremyLondonMDL]

It seems that V-Ray 5 currently alters the mapping of C4D noise shaders when they're used in material channels.

In the attached screenshots, I've displaced a plane using C4D noise, and copied the same noise shader into the color/diffuse channels of the C4D and V-Ray materials. All noise shaders have Space set to UV (2D).

With the C4D material applied to the plane, the material noise matches the displacement noise in the viewport, and in a C4D Standard render. However, when the same scene is rendered with V-Ray the material noise seems to change or move.

With the V-Ray material applied to the plane, the material noise is out of alignment in both the viewport and in the V-Ray render (and the noise pattern looks identical to the C4D material when rendered with V-Ray).

In V-Ray 3.7 this problem doesn't seem to happen.

Does anyone know of a workaround to get the material noise mapping to match the displacement noise mapping in V-Ray 5? (e.g. noise scale settings, material tag offset values, etc.)

Thanks

[YunalZobu]

Hi JeremyLondonMDL ,
could you perhaps share your scene and/or machine, software info, because I was not able to reproduce this on my side.

[JeremyLondonMDL]

Hi YunalZobu, thanks for your reply.

Here's a link to a simple version of the scene, and a series of screenshots showing the results of my renders. When a C4D noise shader is used in a displacer it renders correctly with both Standard and V-Ray render engines, but when it's used inside a material channel the mapping changes when rendered with V-Ray.

My computer is a desktop PC with the following specs:

Intel(R) Core(TM) i7-9700K CPU @ 3.60GHz 3.60 GHz
32.0 GB RAM
Windows 10 Pro Version 21H1
NVIDIA GeForce RTX 2070

Current software is as follows:

Cinema 4D R21.207
V-Ray 5 for Cinema 4D, Update 2 (v5.20.00 from Dec 7 2021)

Thanks for your time on this.

[JeremyLondonMDL]

Hi again YunalZobu

I just noticed in your screenshot that the mapping of the material noise doesn't match the mapping of the displacement noise. The white and black squares should be on the highest and lowest parts of the displaced mesh, but they're misaligned.

I assume you've used a V-Ray material in your example, which is why the texture mapping looks the same in your viewport and your render, but they both don't match the displacement. The same thing happens in my files, as shown in the last two images of my original post.

If I use a C4D material instead, the noise matches the displacement in the viewport, but changes when I render the scene with V-Ray.

Thanks

[YunalZobu]

Hey JeremyLondonMDL ,

thank you for the additional info and the file. You're right the mapping was 1:1 between the viewport and the render, but not matching the displacer setup.
The only way I managed to get all three (displaced geo - viewport - render) to match was using the BakeTex.
It's an additional step, but it gets the exact result you are after

[aleksandar.kasabov]

Hello JeremyLondonMDL,

Thank you for bringing this to our attention. I have reported this issue to our developers (bug ID: VC4D-1241). I will let you know if we have any updates on the matter.

Until then, as Yunal mentioned above, you can put the noise shader inside VRayC4DBake shader.

Thank you.

[JeremyLondonMDL]

Thanks YunalZobu and aleksandar.kasabov

Placing the C4D noise shader inside a VRayC4DBake shader as you suggested works perfectly. It also works when the C4D noise shader is animated, so it seems to be a complete workaround for my purposes.

[akos_kiss]

Hi!

We ran into a bunch of problems with the vray c4d bake shader and displacement tag. A few updates ago the colorizer shader was added to the supported texture list but when we used it for displacement it simply didn't render anything i.e. the object that had the vray geo tag simply didn't render ( it was not visible to the camera).We had to add the c4d bake shader to every material element that used the same noise so the masks and textures aligned. This is a bit frustrating because in the supported features documentation the colorizer shader is supported. Currently there is not other way to remap black and white shaders or textures with a gradient, other than the colorizer shader. As I can tell there is no vray shader that can be used for color remapping.
The misalignment with the bake shader and the native c4d noise is something that is not ideal.

The bake shader is also an issue for close up shots and more wide shots. Because we have to crank the bake resolution really high so that the displacement looks acceptable. ATM we don't know if we can use vray for a bunch of macro shots because if we zoom in the displacement doesn't hold up. Even at 8 or 16K bakes. And of course the render times are really high, because of this.

The other issue is that with the the vrayc4dbake shader doesn't bake or support animated noises when used for displacement. At least in the latest version it doesn't render the noise when rendered in a sequence. It updates in the vfb when we render single frames. But when we start rendering in a sequence it simple doesn't update the texture in the displacement.
I've already made a few post about different errors and bug with the vray displacement. But this is a new and really frustrating one.

If i use the displacement tag with a hierarchy it glitches out unexpectedly, when i use it with a generator it does the same. When i try to use an animated noise shader with displacement it simply doesn't work. Only if i render every frame one-by-one than it works..... somewhat. Because for some reason sometimes it jus forgets that there is a texture used for displacement and renders a flat object...

When will the displacement tag be fixed? What solution do you suggest for the colorizer and vrayc4dbake shader for displacement? Or just simply the noise shader with vrayc4dbake shader, As they also don't work. As they don't seem to work right now.

Here is a link for a test scene and an mp4 for my test.

I want to use vray for all of our production work but these types of issues make it a really disappointing to work with, as it make the day about troubleshooting technical issues rather than making something look nice....

[sirio76]

Maybe I'm missing something but here I can do a lot without backing shaders. If you choose the correct colorizer/filter order you can also animate the noise.

Remapped noise+displ:



Bump channel:



Remapped+colorized+displ:

vray_displacement_bug_test_04 3DRnB.c4d.zip

[akos_kiss]

Thank you sirio76 for taking the tim and looking into the issue.

The main issue is that the displacement is not animating. The noises are set up the same and there is an animation speed, but noise in the materials is animating correctly but the displacement is not updating.
I saw that you changed the displacement type to 2d but unfortunately we need the full 3d displacement as the camera moves and lighting changes are substantial.

The other issue i have is that we have to crank up the displacement max subdivision to 4096 and the edge lenght down to 1 or 0,2 in some cases. to have nice looking edges. And i have to do this regardless the polygon count of the underlying mesh.
For a noise like sema or displaced voronoi we need really high settings.

For now the edge issue is secondary. I will make a simplified noise from the one we use in our scenes tomorrow.

The main issue is the displacement animation. If i start and interactive render and i just randomly click around on the timeline i can se that the lighting is changin on he object and it ooks like its from the displacement but actually the dispalcement doesn't change. all the edges are static and if i move the camera up close the object geo is not displaced. It only shows some kind of light-bump movement. This is really strange. If i restart the IR the displacement will update.

The colorizer is a lot more intuitive than the filter shader. As the gradation curves don't work too well at the moment the colorizer offers an better solution because we will use the colorizer to drive texture masks and color changes during the animation. And as it is supported we thought that it can be use with the displacement tag. Unfortunately this is not the case as the colorizer doesn't work with dispalcement tag. No problem because we have the vrayc4dbake shader. But unfortunately this came with an new set of issues. as the bake shader changes the mapping of the noises. In this situation we have no other option than to use the bake shader everywhere.

This led to my main issue that the bake shader does not update with the animated noise shader. This is really strange because a few post above it was stated, that it works. On my end this is not working with the latest update with a simple noise in the bake shader or the with the colorizer (with a noise)

I hope i made this complex issue a bit more clear with my lengthy rambling

[sirio76]

I've updated to the latest build and indeed the noise animation do not work anymore using the production render (it works only when updating manually the IPR). Regardless of this problem, there is no need to to rise the displacement subdivision that much, it is a lot more effective and fast to pre-subdivide the surface before mapping the displacement.
Usually with a mesh subdivided in square of 10x10cm you can get perfect results with barely 20 subdivision:

[akos_kiss]

Thank you for checking it with the latest build. I was thinking maybe something went wrong on our side with the animation. I'll definitely check the subdivision count, and try to do a few tests, how it holds up!

Unfortunately the scale of the scenes varies a lot, I will try to figure out the connection between the polygon size, the max subdivision and how close can we get with the camera