multiple UVW?

[STRAT]

Vray will not render an object with more than 1 UVW mapped material assigned to it. normal C4D AR does.


has this bug been sorted out in 1.2?

[MartinWeber]

I don't think this works in 1.2.5, does it?

[stefan]

this is no bug but a limitation, due to the way c4d handles UVs.

we have plans to support this in free vray1.5 update, it will be complicated to make but is on our todo list

best greetings
Stefan

[MartinWeber]

Thanks Stefan.

I am running increasingly into situations where I need different UV-sets or different tiling for the displacement map. I noticed that the displacement material does not honor the material tag's tiling. Is this also a current limitation or actually unintended?

Thanks,
-Martin

[stefan]

this is actually a very useful feature and intentional, to use other mapping on the displacement than in material:-)

so you can set the mapping to UV in displacement and to cubic or uv with another scaling in the main material- this is a big advantage in usage, and we of course keep that. you can set both totally separate in mapping.

cheers
Stefan

[MartinWeber]

Well, what I meant is when I set the material tag containing the displacement material to a uv-tiling of 10x10 it does not work.

See the attached scene:
When I set the displacement to 30x30 it does not work. When I scale the UVs by x30 and set the tiling to 1x1 it works but then the UVs do not make any sense for other materials.

[stefan]

no that wont work in that way.

you needed to set one to non UV to controll different(flat for gras is best)

[MartinWeber]

Stefan, it seems you do not understand: When using 2D displacement maps the uv tiling does not work. No matter what mapping type I use, the displacement material does not work with tiling.

I also cannot use flat projection when I have flat and sloping areas for grass.

Even while there is no support for multiple uv-sets I would like to use different tilings for different materials.

[stefan]

ah ok, with 2d you also might have this- and some other limitation yes, but it is much better to use 3d displacement in almost all cases, it has higher quality and lot more options.
the 2d displacement is the old way and not the same capabilities as the newer 3d displ.

p.e for grass 3d is much better and gives you the options you want.
by the way- also flat mapping is most time good and easiest for slightly sloping landscapes, your example above fits flat mapping well p.e., i used that myself often in past (now i do grass with hair all time which looks most real, fur is also a nice option)

in that case if you really want to stick to 2d displacement you needed to scale the uv manually in bodypaint so texture uv and set resolution fit together, is also easy. (and maybe use flat for one of the textures, looks good and natural too, believe me)

i can look at your file after easter holidays so i fully understand what you mean, but for all displacement options best use 3d, it is far superior and very fast (specially in new vray 2 core we use)

there are really many options possible to make a perfect grass landscape
stefan

[stefan]

p.s i had short time on laptop and setup a nice displ 3d grass n that scene, if you want email then i send it back to you(i cant upload from here)

stefan

[MartinWeber]

Thanks Stefan.

The problem I have with 3D displacement is that with larger image sizes (>2.5K) and a subdivision of >40 for the 3d displacement in almost all my scenes with larger areas the RAM usage goes beyond 24 GB and the displacement process forces Vray to a single thread which results in less than 5% CPU usage overall on our 12 core/24 thread workstations.

I have scenes that render in 8 min at 1.5K resolution but are still in GI prepass after 40 hours when I increase the image resolution to >2.5K. That's why I resorted to 2D displacement. (try the scene I have attached with 3d displacement and a resolution of 4K).

I also tried VRay Fur and it has the same limitations like 3D displacement.

I have spent weeks trying to find the optimal way to do larger areas of grass, including surface spread, Vray fur and displacement. So far the 2d displacement is the only solution.

[stefan]

Well then why not make 2maps that nicely fit together the 2d displacement, both using the same uv, thats certainly also possible

Stefan

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By the way if you deavtivate view dependent 3d displacement is not dependent on output size

What you say speaks for a wrong setup a bit
If the displ renders fine in small res i does in big res using same ram
Make sure to have viewdependent off.