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unable to retopologize

ZBrush Usage Questions
#1

First post. I’ve tried to find something similar to this problem in the forum but couldn’t. If this has been answered before, i apologize.

I’m a relatively new Zbrush user, using 3.1.
Windows XP 64bit
AMD Athlon 64 X2
Dual Core processor TK-57
1.90 Ghz, 2.87 Gb RAM

I’ve been trying to use the topology tools to merge two separate models: One human head i had sculpted and retopologized previously, and a human body that wasn’t done by me (imported as obj, turned to ztl).

I’ve gone through the process of turning the separate models into a single one without too much trouble, effectively leaving me with a body with an incomplete neck with a head hovering directly over it, and was going to try and use the topology tools to bridge the gap between the head and the neck.

I create a new zsphere, go Rigging->Select Mesh, select the model, then Topology->Select Topo, select the same model. The problem here is, the topology “net” that should be surrounding the model doesn’t show up at all, essentially leaving me to retopologize the whole thing from scratch. Zbrush doesn’t even take the time to make the calculations or give any sort of warning, just sits there like nothing happened.

I’ve tried it on a couple different models, see what produced what. Eventually, using the same model with different subdivision levels (deleting the unused levels beforehand), it seems to me that the program won’t go beyond a certain polygon count. Between levels 4 (about 8000 ploys) and 5 (over 30000), it’ll work fine with the former but simply disregard the latter. I can’t confirm this though, and even if i’m right, i don’t know what i can do about it.

The body model i’m trying to merge has triangles in it, so i can’t reconstruct the subdivision, short of retopologizing the whole thing myself (which i’m kinda starting to consider in the lack of alternative).

Thanks for your time.

#2

May be too many points in the mesh you’re trying to select as a starting topology. (Need pictures of the models you’re trying retopo and the mesh you’re trying to start with.)

Hand crafting a mesh if your starting meshes are dense and full of triangles may be your best option.

-K

#3

Not sure about this, as I’ve never used retopology to join meshes. If I understand your problem, couldnt you retopologise both seperately and then join then using mesh insert?

#4

there is a 15000 poly limit on importing topology

#5

Not if he wants them to be one continuous , seamless mesh, which I assume is the point here.

#6

I found a workaround.

Kerwin

Well, all i did was get another body with a much lower poly count (the first one was over 70000 - sorry, but i got rid of it already), and i haven’t reattached the head but the retopology sems to work just fine, so i’m fairly sure now it’s an issue with the number of points. The new body still has triangles, but now i can try and correct that without retopping the whole thing, and the poly count is so low it might not matter - my end goal will involve cell-shading, or some other method to the same effect, though i’m pretty sure it’s kinda naive to think the benefits of good topology only go so far as texture and UV mapping, but i guess i’ll have to learn as i go along.

Gordon Robb

I’ve retopologized the head myself, but not the body. I’ve only used insert mesh once, to place the head on the body, but that still doesn’t seem to link the geometry (not as far as i could see, at least), which is what i wanted to do (i want to rig it in poser once it’s ready, though i’ve read the transition process isn’t trouble-free).

BTW, this thread only appeared (at least on my pc) some 19 hours after i first posted it, don’t know why. During that time, i thought maybe it hadn’t posted it right, and posted it again, so an identical thread might pop up sometime. I’ll try to delete it (if i can even do that) if i see it, but just in case anyone bumps across it. Sorry for the hassle.

EDIT: this post took a while too, so i hadn’t seen the following 2 replies yet.

spaceboy412

-that confirms what i thought, thanks for giving me the exact value

Bingo_jackson

-exactly

#7

You can combine meshes using Mesh Insert and you can also merge subtools with Subtool Master. If the head is floating over the body, then I would suggest getting some neck geometry in there before you attempt to retopo. If need be, just stick a cylinder in there, combine the three meshes, then use the clay brush to blend the seams between them. Now retolologize.

Also, you shouldn’t have to retopologize the head if you like the topology you currently have for it. When you’re in Edit Topo mode, just hold SHIFT and wave your cursor over the head area to get that old topology back.

#8

Yes, i used Mesh Insert even though i had the subtool in place to begin with, just because that’s how it was done in the tutorial i’d seen. I was planning to just unite the points between the two meshes without a model like a cylinder to bridge the gap beforehand, but i think i’ll do as you suggest now.

As for retopologizing the head, admittedly i didn’t know how much of an advantage it would be, if any, given the use i’ve got planned for it. I just thought better safe than sorry, and given that i was gonne have to use topology for this step anyway. And i was gonna have to learn it anyway, if i’m serious about this.

#9

Am I missunderstanding you? I have retopologised a 10 Million poly mesh.

#10

There’s a difference between retopologising with a high density reference mesh, and editing the existing topology of a mesh. In the case of the latter, there is a poly limit to what you can import into the process. This is what I assume he is speaking of.

You should receive a warning to that effect if you’re trying to do it though.

#11

A, your talking about when you do ‘select topo’

So is the problem that one of the object is a hi res mesh (with no lower res), then I go back to my first option, just retopolgise (from scratch), the one that is hi res. then when you have a low res one (with sculpted detail), use the retopolgoy tools to merge them.