Hello everyone.
I’m having some difficulty with polygroups. The first picture is what the polygroups should look like. The subdivision level is 5. After I decrease the subdivision level to 1, then put it back up to 5, the polygroups distort, resulting in picture 2. I’ve tried using Auto Groups, UV Groups, and Group Visible but it always distorts. Can I fix this, or do I have some kind of bug in the system? I’m running this on Windows 2000.
Could you describe your exact workflow?
Sure. All the modelling was done in zbrush. First, I created the zspheres for the body. Then I sculpted the character using the different tools available. After subdividing it to level 5, I masked the outline of the clothes, pressed “HidePt” so that the only thing showing is the clothes, cleared the mask, and then went to Deformations and used the inflate tool. After that, I went to polygroups and pressed “group visible”. When I lowered the subdivision level to 1, then increase it back to 5, the polygroups are distorted.
I noticed that when you lower the subdivision level to 1, the polygroups become different. This is due to the number of polygons. But then, when you increase the subdivision to 5, the polygroup takes the shape that it had in subdivision 1, and uses that in subdivision 5. Take a look at picture one. This shows the polygroup that I created. I then lowered it to subdivision 1 (picture 2), and then increased it (picture 3).
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Is your model still connected to the ZSpheres? If so, then you won’t be able to define polygroups effectively because the ZSpheres calculate a new mesh every time you turn on the preview.
If you are sure that your ZSphere structure is complete, you may be able to overcome this by turning the preview off and pressing Tool>Morph Target>StoreMT. This tells ZBrush to calculate the final mesh which will be used every time you activate the preview. It should also be done before you ever start texturing or sculpting a ZSphere figure.
If this doesn’t resolve your polygroup problem, you’ll need to skin the model to disconnect it from the ZSpheres.
Thanks for the response and suggestions, but unfortunately; I’m still getting the same problem. I attached a zscript to show you what is happening. Maybe you can see what I’m doing wrong.
Polygroup Problem.TXT (10.5 KB)
A quick test on one of my old models shows the same problem, losing polygroup detail going to lower, then returning to higher levels. First I’ve noticed this, since I usually generate polygroups at lowest level.
Maybe Aurick will have a simple option for bypassing the problem…
Meantime, one possible remedy: generate and store a mask based on the polygroups at level five, then use the saved mask to recreate the groups when returning to level five again. Awkward but it works. (Though lots of groups means storing a mask for each…)
Sven
What is happening here is a byproduct of multi-resolution subdivision editing.
Polygroups are basically defined from the base level going up. The polygroup info for the highest levels is not stored anywhere. Instead, it’s interpolated from the base level.
When you create a polygroup at the highest level, ZBrush lets you do that. But when you go down in levels, the polygroup info that can’t be translated to the lower number of polygons that you now have gets discarded. So when you get down to level 1 you have a case like what you show where only a single polygon (in that example) is in the group. Now when you go back up in levels the polygroups get reconstructed based on that lowest level. Anything that can’t be derived from that level no longer exists.
Try using my Select-It plugin. This was designed to let you easily store and manage selection sets.
Thank you very much aurick for taking the time to respond to my question. This really helped me greatly. And svengali, your suggestion is a great one. A lot of people have told me about the great service provided by the ZbrushCentral. I knew when I bought Zbrush, it would be a great investment. I guarantee that I’ll be buying future products made by Pixologic.
In about 2-3 weeks, I’ll be creating my first free fully rigged character model (modeled and textured entirely by Zbrush [and maybe Photoshop]) for Maya 6.0. His name is Billy Bob. He’s actually the first picture in this post. I hope to create many more rigged characters over the next few months. I’ll also provide the models to anyone who wants to rigged them for other programs. The reason I’m doing this is so that newbies and experts can practice with them and even put them in their demo reels. I’ll make sure everyone knows that the models where created and textured in Zbrush.
Thank again.
