Optimizing figurine/busts workflow

Discussion in 'Design and Modeling' started by hardboilr, Aug 30, 2013.

  1. hardboilr
    hardboilr New Member
    Hey guys and gals.

    I produce small 5-7 inch figurines, head busts and other organic objects for printing in the color sandstone material.
    Everything is created in Zbrush and in a typical project, I will end up with around 10-30 subtools and several million polygons. The subtools contains polypaint.
    In preparing the final model for print, I do this:

    1. Merge all subtools
    2. "Dynamesh" the merged object to create a lower resolution, unified model.
    3. Clean and smooth various areas.
    4. Export to Blender
    5. Run analysis to check for problems such as non-manifold areas etc.
    6. Back to Zbrush to correct those errors
    7. Export final model from Zbrush in WRL with polypaint data.

    I find that the biggest challenge in this workflow is maintaining a satisfactory level of surface detail and color resolution. In step 2 I obviously loose some detail, because I have to be within the set polygon limits. Also checking a heavy model for errors is almost impossible in Blender.
    In a non-color scenario I would obviously decimate the model, but because the color is tied to the polygons, this is not an option.
    I have also tried various UV-mapping workflows; auto generating UV-tiles in Zbrush, but it creates seams and often causes crashes, due to the density of the model.

    Do you guys have any suggestions as to how I can improve my workflow? Basically getting the highest amount of surface detail and color resolution without exceeding the data limitations? Thanks alot! :)
  2. aeron203
    aeron203 New Member
    You have that about right. As you mention, the only major improvement you expect would be using textures instead of vertex colors (since Shapeways has a 1m limit), but that becomes problematic on large models. Zbrush is excellent software, but its automated UV generation is not as advanced as many other programs. It may be "Naive" so that it can wirk on such huge models, but resulting "tiled" map cannot be resized wuthout artifacts, and the Shapeways 2k texture limit will not be sufficient to hold the detail. You may be better off exporting and building the mapping in other software. Depending on your model, you may get better results with mapped textures, even if you must decimate it more for the algorithm to be able to handle it. 3DSMAX and Maya unwrap well of course, but on the free side even Blender has some good unwrapping. Combine that with Meshlab to project your multi-million vertex polypaint work over to a nicely mapped decimated version, and you could see significant improvement.

  3. bartv
    bartv New Member
  4. BossMode
    BossMode New Member
    I could only speak from my experience. I've only done one color 3D print for Shapeways but I have done several (non-colored) for work. Here's the workflow I used:

    1) Sculpt in ZBrush. At this point I have no UV's. I'm also working between Maya and ZBrush during sculpting phase. For certain pieces I prefer the precision of Maya.

    2) So I finish the sculpt and I generally have 8 - 10 subtools. Each subtools generally has 6-7 subdivision. I specifically did not use Dynamesh for reasons I will explain later.

    3) Now I have to apply UV to the model. I also want to only have one texture map (just to keep it simple). For UV's I like to use Maya to create the seams and then use ZBrush to unwrap the UV's.

    4) Combine all (merge down) subtools with subdivisions. This was easy as long as the subtools shared the same amount of subdivisions. That way you should still have all your subdivisions.

    5) With the combined mesh I GoZ into Maya. It should automatically export the subdivison 1 model into Maya. This is why it's important to have the subdivisions intact otherwise Maya has a hard time handling millions of polygons. From Maya I layout my UV's and then GoZ back into ZBrush.

    6) So I'm back in ZBrush with proper UV seams and use UVMaster to unwrap the model.

    7) Paint model in ZBrush.

    :cool: After I'm happy with the colored version I use Decimation Master. Make sure to have "Keep UV's" selected.

    9) So I'm almost done here. My model is fairly simple and I have some experience 3D printing at work so I'm very confident the model will pass. I use the "3D Print Exporter" from ZBrush and export out a VRML file. When the VRML file is exported the texture is also exported along with it.

    10) Zip up the VRML file and the texture map together and submit.

    Oh and as to why I didn't use Dynamesh... because I wanted lower subdivisions to be able to create UV seams in Maya. I've tried exporting Dynamesh into Maya but it just crashes. There are two ways to that you can create lower subdivisions from a Dynamesh model. One is the "reconstruct subd" button. Unfortunately it doesn't always work. The other is to duplicate your model and use ZMesher to create a lower poly version. Then project the high poly version back onto the lower poly version while subdividing.

    Anyways i hope this was somewhat helpful. Sorry for babbling on.