vray displacement mod support for multi different map channel

[Bigguns]

Hi,

I would like the Vray displacment mod to support multi different map channel , let's say I have some uv's done in map channel one, and then for a certain purpose( like it happens on my last project..) I need an other sets of uv's, the vray displacement mod only suport for one at the time.. I tried to put 2 vray dis.. with the 2 different map channel , but at render time it was only supporting one.

So, would it be possible to include it in the next release pleaseeee so it can support multi map channel at the SAME time.

Thank's

[Svetlozar Draganov]

Thanks for the feedback - I'll add your request into our system and I'll let you know when such option is available.
Meanwhile you could workaround this limitation by baking the composite map into a single texture and use it into VrayDisplacementMod.

[Bigguns]

Hi thank's for the consideration.

I cannot do that, since the 2 uv channel have totally different uv's.

[Svetlozar Draganov]

Could you please give us more information about what exactly is your scene setup.
A sample scene file will be the easiest way to explain us what is the exact workflow.
What I had in mind is to to first bake the separated textures with different uv-channels into one single texture and they to use it in VrayDisplacementMod.

[Bigguns]

I think I need to explain it better.

Not everybody knows that in 3dsmax you can have multiple map channel in the unwrap. So it means, you can have different uv's set, for the SAME mesh. So you can have 2 different uv's for same model.

applying a new channel with, let's say a uvw planar is easy, you just change the channel of that part and that's it. But, things a re a bit more complicated when you need to do it in the unwrap, it ask you,when you change channel, do you want to ABANDON or MOVE the uv's. You have to say ABANDON, otherwise it's just moving the uv of map channel one to map channel 2... and after you finish to do your second map channel in the unwrap, you need to collaps it! And then, if you want to edit it again later, you ca, but each time you have finish to do the things you had to do in the unwrap, you have to collaps it so the change are baked in the unwrap.

So, what I was doing is, I had a character, I did at first an unwrap on the character, in map channel 1, everything was working fine and I did a diffuse and a displacement map for this uv's. but then, I realised I needed different uv's set for the displacement map (for optimisation of details purpose etc) , in fact, my displacement set up use MULTIPLE LAYERED displacement maps (for displacement animation and other things) so,let's say I had 1 maps of displacement in the uv channel 1, and then, completely different uv's in channel 2 and 3 or more displacement map for this channel (2).

So the problem was, when I add a vray displacement mod, it could only handle ONE uv channel. Even if I put 2 vray displacement map with the first one at map channel1 (plugin in it my displacement map channel 1) and having an other vray displacement mod over it in map channel 2 (with my multiple displacement maps( in a compostie) channel 2 plugged in it, nothing work. It only take one of the 2 channel, it could not handle both, while in mr, it work, I just have to copy the composite directly in the displacement slut in the shader.


I hope it clarify's it, if not I can make a simple scene to show the problem.

And also, Vray is handling with difficulty's the composite when using displacement map... don't know if the problem is Vray or the composite.

[Bigguns]

Do you have an email where I can send the file ? I made a simple scene to show the problem

thk's

[vlado]

When using 3D displacement/subdivision, you can use any mapping channel that you like; there is no restriction at all and it works fine. 2D displacement however can only work with one single mapping channel and this cannot be worked around. So I will be closing that issue that Svetlozar opened.

Best regards,
Vlado

[Svetlozar Draganov]

I just followed vlado's suggestion and indeed this is only limitation for 2D displacement type - the other two types 3D displacement and subdivision are working correctly with composite map with assigned textures with different uv-channels.
Here are a few images:
1- This is simple diffuse test where the big-checker map uses uv-channel 1 , and the small-checker-map use uv-channel 2 which is rotated 45 degrees. Both maps are mixed with composite-map and this same map is applied to diffuse channel.
2- Here how the displacement looks like if 2D type is used - the small-checker map is no-longer rotated which means that the uv-channel 2 is not taken into account.
3-But if the displacement type is changed to 3D displacement or subdivisions all uv-channels are taken into account even though VrayDisplacementMod channels is set to 1.

SceneFile=>Displacement_MultiChannel01.zip

[Bigguns]

ok thank's that's what I readed in the help file to

But why 2d mode do not support it? Is there a way to make it support it? Because the 3d displacement was much slower in my old test, I read in the doc it's faster now, I will do some test on my character to see..

[vlado]

But why 2d mode do not support it?

It is a specific algorithm that operates in texture space; I don't know how to extend it to multiple UV sets.

Best regards,
Vlado

[Bigguns]

ok thank's Vlado.

I have a question, I made a test render comparaison between 2d displacement and 3d one to see if there is a difference.. and there is one.

In the 2d displacement mode, I put a resolution of 7k, I know it's very high, but I have very small high frequency details and to get them all, 7k was required. With the 3d displacement, I noticed that these small high frequency details where less present, I try to put the 512 instead of 256 but saw no difference..

So my question ,is there a way to get the same definitions in details with the 3d displacement as the 2d one ?

[Svetlozar Draganov]

Every displacement type is calculated by different algorithm hence the end-results will not 100% identical.
In general 2D mapping type is more sensitive to high-frequency details than 3D mapping.
3D mapping is controlled not only by Max.Subdiv. parameter but also from Edge Length value - so you may try to decrease this value even under 1.0 in order to get as much details as possible. Also you may consider decreasing or completely removing Texture Filtering in order to gain more details.