disp map from obj file

[ndog]

[This topic has been transferred to the: Questions & Troubleshooting Forum.]

I used Z2 to detail a low res obj file and instead of saving the high res model as a ZBrush tool I saved it as a obj.

Is it possible to extract a displacement map from the high detail obj model?

[Pixolator]

Yes :)
ZBrush can recreate the lower subdivision levels of your high-resolution mesh. Furthermore, this feature is not limited to ZBrush-generated high-res meshes, you can use the following procedure to recreate lower subdiv-level of any properly-created subdivision surface.

This should be helpful when...

1. Reconstructing the lower subdivision-levels of a ZBrush generated high-res subdiv-surface (such as in your case).

2. Reconstructing lower subdivision-levels of a mesh which was previously subdivided (and optionally detailed without changing vertices&poly count ) in another application. In order for this to work properly, the imported high-resolution mesh should be a mesh which was generated by subdividing a lower-resolution mesh using standard subdivision rules( i.e. quad-polys are divided into 4 sub-quad-polys and tri-polys are divided into 3 sub-quad-polys )


Here are the steps...

1. Launch ZBrush.

2. Press the Tool ::Import and import the high-res mesh.

3. Press Tool ::Geometry ::Reconstruct Subdiv. ZBrush will then analyze the mesh-geometry and if possible, reorder the vertices/polygons while reconstructing a lower subdivision-level ( mesh details and UV coordinates remain intact). If the reconstruction is successful, continue with step 4, if not then skip to step 5.

4. Switch to the newly-reconstructed lower subdiv-level (Hotkey: SHIFT+D ). Repeat step 3&4 as needed (Don't go too low, when the low-res mesh contains less than 1000 polygons; go to step 5).

5. You now have one or more subdiv-levels reconstructed. Export the low-res mesh and generate the displacement or normal map. You may also want to save the reconstructed mesh as a ZBrush tool in order to retain the subdiv-levels.


Hope this helps :)
-Pixolator

[ndog]

Fantastic! That worked out great, thanks for the detailed procedure.

[Shrek]

I have tried generating an alpha-map to use as displacement in Max with a 1024x1024 resolution and with 2 divisions set in the displace-settings on a quite dense mesh (a body modelled in Max with 20'000 polygons). The process starts and is near the end of it when ZBrush crashes. Maybe the solution is to rebuild the mesh as it is described here? I have read a ZBrush tutorial, however, where the model looks just as high-poly, and there it works fine... Is it just a matter of too many polygons?