Vray + ZBrush Displacement seams

[TishoChaos]

Correct me if I am wrong, but to properly unwrap a 3D object in front viewport in max includes a lot of detaching of vertices, elements, moving around and rotating, ZB on the other hand from needs only the 3D object as it is and it automatically assigns the correct uvs around it in projection master if I am correct. So, which one is more time-consuming and difficult?

You can have a look at this - it is the ZB forum, I think it requires you to register first.
http://206.145.80.239/zbc/showthread...&page=23&pp=15

[trixian]

Not sure what you mean by unwrapping in the front viewport though Tisho, but sure, unwrapping the uv's in max is more time consuming, and can even be slightly painful, but is usually worth the hassle. This becomes very evident when trying to make uv coordinates that are placed so that texture stretching is minimal. (Not the static stretching, but the stretching that occurs when animating the head, jaw and morph shapes).

[ngrava]

Well, I use Z-Brush and Vray all the time. I actually used to run into this issue quite a lot until I finally discovered the way that works for me:

IN ZBRUSH>
1.) Build your base model in Z-brush with Z-Spheres or other modeling program (Silo, Modo, Max, whatever).

2.) Save the tool as a polymesh in ZBrush or import form other program. You should be sculpting on a Polymesh and not the original Z-spheres model.

3.) Choose GOV or AV before you start sculpting. Subdivide (to level 7 or so) and Sculpt your displacement... Don't forget to save the tool.

4.) Go to the base level (Level 1) of your mesh and create a displacement map at a very high resolution. I usually just crank it up to 4k but you can make it smaller is memory is an issue. I use "Smooth UV" and "Adaptive" when creating.

5.) Go to the "Alpha" menu and choose the newly created Alpha Map, flip it vertically and export as a Tiff image.

6.) Export the base mesh as an OBJ.

IN MAX>
1.) Import the OBJ and put a VrayMtl on it.

2.) In the material editor, add the TIFF Image to the displacement slot. Sometimes I stick it in the Bump slot too if it still looks to soft in the end. Make sure to turn off filtering in the texture map. This is important because Max's filtering really messes up 16 bit per pixel images.

3.) Add a VrayDisplacement modifier to the mesh.

4.) Drag and drop the displacement map from the material editor to the displacement slot of the VrayDisplacemnt modifier. Choose to make an "instance" of the original

5.) Choose "Smooth" Not 2d or 3d! This will smooth and displace the mesh dynamically and helps save memory. In my opinion, it's better to do this then adding a mesh or turbo smooth because it saves memory. When you're rendering huge amounts of data it really does make a difference. besides, if your using a displacement map, Vray is going to control the subdivision level anyway so why not just have it smooth it dynamically as well.

6.) Set the "use tight bounds", "Keep continuity", and "use material" check boxes in displacement modifier.

7.) Play with the "Shift" and "Amount" settings until you get it to look right. In my experience, Shift should be negative one half of the "Amount" value. So if you have an Amount of 4 your shift should be -2.

That should do it. The key to this is not using Max's mesh smooth and letting Vray handle that and displacement at the same time.

[TishoChaos]

trixian: I mean that you can use the front viewport as an align plane for the polygons and later use this as a template for photoshop painting.

ngrava: I am trying what you said now ...

[TishoChaos]

here is what i have - simple object:



basically it is an exported geosphere in dxf format (obj messes up the object) and then subdivided to lvl 5 in ZB, sculpted, then created a 4k displ map with Adaptive and SmoothUV on, flipped the map and exported as tif, exported the object also in obj format (it works this way around).

Then in max, import the modified sphere (middle object on the picture) and apply a material with displace on it with filtering off, apply and a VRDispl mod with all checked and amount 8, shift -4. There seems to be creases similar to the ones Richard has - i have seen this before too.

[ngrava]

OK, I'll try this too.

-=GB=-

[trixian]

Though very handy, and nice to have in the same modifier, the "smooth" part of the vray displacement modifier renders at least twice as slow as using turbosmooth and 2d/3d vray displacement, last time I checked. (Bit off topic but I thought I'd mention it). The reason I find this strange is because the tessellation that is being computed doesn't really seem to be any higher than if using 2d/3d mode. Also, looking at the imap calculation on these objects using the smooth mode, the samples seem to have a more disorganized placement, and can sometimes look quite messy tbh.