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Decimation and keep polypaint?

ZBrush Usage Questions
#1

Hello. I created a model that is almost ready for 3D printing I just have one problem - It has 1.2 mil polys and I need to get it under 1 mil. I know I can decimate but I have already painted it. I absolutely must keep the polypaint data. It has no UV’s. Its just a mesh with polypaint data.

:bulb: My question is - :bulb:

Is there a way I can decimate or reduce in a different way the poly count without losing the polypaint data? I dont have the ability to turn down subdivision levels. I dont have any to turn down. My model is at 1.2 million polys at the moment.

What can I do about this? Is there a solution to this? If worse comes to worse I can repaint but it will take another 4 days, and I really dont want to have to redo it, because it looks so good right now, I surprise myself! :smiley:

Please advise. Thanks for any help. :+1:

#2

Well, the quick and dirty way would be to duplicate your subtool, decimate the duplicate at about an 80% value, or whatever minimum you need to get it to your target polycount, then project the polypaint onto the new mesh from the original with MRGB active, or use the ZProject brush with Zadd/sub disabled and MRGB active.

However, decimation can result in distorted geometry. If you decimate very little you might be ok, but you may see a noticeable loss in polypaint detail, and noticeable errors where the geometry becomes extreme.

A better way would be to duplicate your tool, ZRemesh it to your satisfaction to a base level that subdivides up to the upper polycount limit you desire. It may take some trial and error to get the base level to have just the right amount of geometry where you need it so it doesn’t go over the limit when subdivided. You may find it useful to use the “polypaint” feature in the ZRemesher menu, to “paint” areas where you need more poly density at the expense of areas where you dont, for more optimized polycounts.

Then, subdivide the new mesh up to the target number, and project the detail (both color and sculpting detail) from the original mesh onto it. This will result in a mesh with convenient multiple subdivision levels and well distributed polygons, which will make it easier to transfer color accurately. You can also then use this object to UV map and create a texture if desired, so the color information is no longer dependent on the polycount of the object.

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#3

Thanks for the post. I tried some of your suggestions, but as you stated - I wound up with very messy topology and my polypaint just wasn’t looking right in certain areas anymore. It just caused more stress than I could bare, so I did the unspeakable…I remeshed it and now I am starting all over on all the polypaint. Im a bit upset about that, but I have to count it as a lesson learned, thus I keep telling myself all day after I remeshed… “ALWAYS BE AWARE OF YOUR POLYCOUNT!” :roll_eyes:

I check poly count every few changes whether painting or sculpting just to make sure. So far so good. It would be nice to see something in release of Zbrush 5 where if you screw up like I did, there could be way of maybe exporting powlypaint data as a separate file and then re importing on a new mesh, or something like that… :sunglasses:

Thanks for trying to help though. I appreciate the post, sir. :+1:

#4

It shouldn’t ever be necessary to totally lose your polypaint. As I said, the polypaint from the original model can be projected onto the newly remeshed one.

When you tried to decimate, did you move the “% of decimation” slider up to about 80%? That might produce acceptable results.

Otherwise it’s just a matter of re-meshing a duplicate into a more efficient mesh, and projecting the detail from the original. You shouldn’t have to start entirely over. If one million polygons is not going to be enough resolution to hold your polypaint detail, you should look into a textural solution if that is possible.

Also, be sure to use tools like Zmodeler or the delete loops function to remove geometry in areas at the base level geometry where you dont need it it for color and sculpting detail.