ZBrushCentral

Multimesh merge while keeping UVs, topo and materials

ZBrush Artworks
#1

Hi!

I´m trying to achieve the following process and would love to know if zbrush is capable of doing this:

  1. I have a character build out of several mesh-parts. Some of the extras intersect the main mesh. Each Mesh has a good topology+UV and is well textured with diffuse, normal maps etc.

  2. Now I need this multi mesh character fused into a single mesh with no “inner parts” just one single closed shell mesh.

  3. While fusing I want to keep as much of the old topology as possible, as it is a well made topology. Perfect would be if only the new connection meshes that are necessary to build the new shell mesh are fused into the existing ones.

  4. I want to bake the different UVs into one and keep all textures incl. normal maps etc. in there original place fitting to the new fused shell mesh.

Now my questions:

  1. Is this process achievable in zbrush? If yes then are there any tutorials on that or what are the main steps/functions to use?

  2. If not all of this is possible, which of the steps are possible? And for the non achievable parts: Do you know any workarounds that help coming close to completing the process but maybe with some extra work in another program?

Thanks!

Sascha

#2

A Boolean Union operation should be able to combine the meshes, preserving most of the original topology while only changing the areas where the different models join together (it would need to change the topology of these areas based on what you’re asking). The issue you’ll run into is that because this operation will ultimately change the final vertex count and vertex ordering, your UV data will be lost (polypaint will be preserved). This is not something you’ll be able to recover inside of Zbrush, which relies on the vertex ordering for transferring UVs. You can use other programs that have tools designed to let you transfer attributes (including UVs) between different meshes based on positioning (like ‘GATOR’ in Softimage, which will let you transfer UVs by looking at the Closest Vertex or Surface). I would still expect that some manual cleanup will be required in these altered areas however.

The second problem you’ll run into is that you want to use normal maps (I’m assuming it is a tangent based normal map?). The issue there is that when a normal map is created, it is created using a specific set of information from the low poly model (such as the tangents and vertex normals). The normal map is designed to apply its own texture information to that data in order to recreate the intended result. And by combining the meshes in this way you will likely alter some of the information that the map was designed for. This shouldn’t be a problem for the unaffected areas of the mesh, but it could lead to artifacts and noticeable seams where the different models merge together. If it were an object space normal map then you might be able to use a tool like Handplane 3d to successfully turn them into a proper TS normal map for the new mesh, but that might still be a long shot.

#3

Hi Cryrid,

thanks for your input! Ok. That looks like not at all “within zBrush”. At the moment I hope to get it done within 3dcoat as there are some promising approaches. But your concern about the normals will probably be a problem there too.

So let´s see.

G*S