ZBrushCentral

Scale between Zbrush/3ds Max, displacement errors

ZBrush Usage Questions
#1

I wanted to set a model that already has subdivisions and detail to real world scale for rendering in Max. Looking around online, it seems the best thing to do is set the scale of your base mesh in Max first, then export it and import it into Zbrush manually, then add layers/details… so, I exported everything, both hi res and low, brought it all into Max, grouped it, scaled it, then exported everything and brought it back into Zbrush, projecting details, etc onto the rescaled low res mesh… then I shot the displacement, GoZ’d it back to Max, added turbosmooth and vraydisplacement and everything seems okay, except for inexplicable artifacts and jagged edges around the eyes and nose. I was also having displacement issues on the model before resizing too, so I was wondering if it had something to do with my settings. I’ve tried all these same settings on the ztools that come with Zbrush and they seemed to work fine… so, I thought maybe my uvws got messed up with all the back and forth… but after redoing them, same issue. Here are screens of my displace and vray settings, if anyone can offer some insight…

smooth

dispsett

matset

tsmooth

vraydisp

vray

#2

Hi @tehMoud

Sorry you’re having some problems ! I know that getting different programs to play nicely together can be tricky.

I’m afraid I cant be as helpful here as I wish I could. Many of your inquiries revolve around getting things to render correctly in Max, and those questions would be better directed toward a resource dedicated to that platform. Other Max users are far more likely to have the specialized expertise you’re looking for. You can hope that someone with the expertise you’re looking for weighs in here and I hope they do, but I’m afraid I’m going to be frustratingly general in my advice.

  • Troubleshoot your scale issues and your displacement issues separately. Get your scene set up and your scale issues resolved early in a project. Displacement can be a can of worms in itself, and there are plenty of things that can go wrong even if your scale is fine. The two problems may not be related, and dealing with them both at the same time involves far too many variables.

  • A commonly misunderstood aspect of creating displacement maps in Zbrush is the need to store a Morph Target if the map must match pre-existing geometry exactly. This is most often necessary when working with geometry created in another program that must match an existing scene.

In Zbrush, the very act of subdividing a mesh will alter that mesh at the base level slightly. This isn’t usually an issue if you export the altered mesh for use with that displacement map as you probably would if your mesh was created entirely in ZBrush. If you export a displacement based on the altered mesh, though, your map is not being generated for the original geometry you imported, and may vary enough to cause issues.

  • The way to get around this is to store a morph target prior to altering the imported mesh. As described in the Multi Map Exporter documentation, a basic workflow is:

    1. Go to subdivision level 1.
    2. Store a Morph Target by pressing Tool >> Morph Target >> Store MT.
    3. Import original mesh.
    4. Set the plugin options, making sure the ‘Switch MT’ button is on.
    5. Press ‘Create All Maps’ to start plugin operation.

I’m not saying this is your issue, just a common one. Displacement problems can be caused by many things–UVs being smoothed differently in the two programs, an issue with UV creation, or just trying to ask a displacement map to do too much are all common issues.

Good Luck!

#3

@Spyndel,

Thank you very much for the detailed response. Unfortunately, I’ve tried all this and have the same issue… I even tried breaking apart my uvws, as noted in step 4 of the article you sent me. I’ve also messed around a bit more with some of the map export settings. So far, no luck.

#4

Finally gave up on vraydisplacementmod. After try just about every possible setting combo, etc that I could think of, I kept getting displacement errors. Switched to the displace modifier and with a little tweaking got it pretty much looking like it does in Zbrush. No idea why this model was giving me so much grief…