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Maya to zbrush import problem: dividing alters my lowest subdivision

Yeah so basically im importing a character over to zbrush from maya. Im content with some things for now, such as her face, but I want to sculpt and add detail to the rest of her in zbrush. The problem im having is that once I hit that Divide button, the lowest subdivision gets changed, and I lose detail on some parts, specifically her eyelids and lip area for example.

I tried dividing 1 level without smoothing, then dividing the rest with smooth on afterwards but it looks weird.

Is there a way to sculpt my maya to zbrush import while keeping features of my lowest subdivision intact?

How do I do this properly?

Replies

  • CheeseOnToast
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    CheeseOnToast greentooth
    You can't just subdivide a model without it changing and losing definition. You'll either need to add additional supporting edges to your base model or use creasing in Zbrush.

    It sounds like your pipeline is a bit backwards. In production, most artists make a basemesh (purely for sculpting/subdivision) > high poly > retopologised low poly mesh with animation friendly topology and UVs. There are exceptions, but this is a typical workflow.
  • Skiffy
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    Skiffy polycounter lvl 15
    Hello Decoyz,

    I had the same issue years ago and realized its just how zbrush handles and represents its displaced data. If you store the initial mesh as a morph before dividing the model and then blend it back in afterwards then it has a tendency to exaggerate the higher levels of sub-division. Zbrush does not do smoothing like you are used to when applying sub-D in Maya or 3dsmax. With Maya the original mesh shrinks because of the smoothing but keeps that as its original source date. Zbrush smooths the model and then tosses the original shape pretty much because of how it stores the data even at the lowest base level. But that is because each step builds on the previous level of information.

    A simple test you can do is to take a new model and add a few divisions. Then go back down to the lowest level. At that point pick a edge or point on the model and keep track of that exact spot. Start going up in divisions again. You should notice that the point does not contract or move at all.

    So now the question I have for you is what is your intention with this final sculpture from zbrush? Do you plan on applying it to a model in Maya using displacement and then doing some CG animated render with an already rigged character? Or are you simply going to bake this info to a new low-poly model?

    If you are planning to use it for displacement then you need to take the zbrush sculpt into maya and bake it as a displacement map to your original sub-d mesh using the baking tools. Or you take the new zbrush model and calculate displacement inside zbrush while taking the altered base level mesh and applying it as a morph onto your previous model inside Maya before it gets displacement applied. There is a bunch of threads on Zbrush central that covers these workflows more in-depth but that is a quick summery.

    Of course if you plan to just use the sculpt to bake normals then I would not care at all about the lowest division anymore. Its the end result that matters.

    Hope that helps!

    Cheers!
  • Decoyz
    Skiffy wrote: »
    Hello Decoyz,

    So now the question I have for you is what is your intention with this final sculpture from zbrush? Do you plan on applying it to a model in Maya using displacement and then doing some CG animated render with an already rigged character? Or are you simply going to bake this info to a new low-poly model?

    If you are planning to use it for displacement then you need to take the zbrush sculpt into maya and bake it as a displacement map to your original sub-d mesh using the baking tools. Or you take the new zbrush model and calculate displacement inside zbrush while taking the altered base level mesh and applying it as a morph onto your previous model inside Maya before it gets displacement applied.

    Of course if you plan to just use the sculpt to bake normals then I would not care at all about the lowest division anymore. Its the end result that matters.

    Cheers!

    Oh damn late reply, sry. Thought this thread dissapeared somehow.
    Thanks for the insight. Yeah I tried the morph thing this week only to be disapointed that it messes up the highest sub division :(


    I'll try to add more edgeloops around the face later and see if it holds up better. ..or I was thinking of simply replacing the zbrush head with my old head in maya.

    My final intention is to bake the hi poly onto a low poly somehow, which I haven't finished yet. My base mesh that I used to import into zbrush is already low poly in most areas at the moment, so I may modify the topology on that for my low poly.
  • Decoyz
    ok so I figured out a solution myself.

    ...I think. so back to my original question, basically in maya I did a smooth on my mesh, with lowest settings, then export that for zbrush. Then in zbrush I replace the second subdivision level using a project all with the maya export and that seems to work out fine so far.
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