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Retopo question

ZBrush Usage Questions
#1

Goodday all,

I have a question about retopologyzing(is that a word?) a Zbrush model.
Currently I am learning Zbrush with a book but it’s a little vague about this aspect of Zbrush.

Because the retopo tools in Zbrush are somewhat limited, and I prefer to do it in Maya with NEX tools. I was wondering how you get all the high level detail back on your cage model made in Maya, and re-imported back in to Zbrush.
Is this possible, and will changing the UVs cause any problems?

Thanks!

#2

Retopology is covered in detail in the online documentation. See my signature.

#3

Yes of course the first thing I do is search the manual for a bit, but what I often find is that the zbrush manual is very vague and abstract in it’s explanations.

Below is a step by step process for importing topology into Zbrush from the manual. Now call me stupid but by step 9 I am starting to loose it but I totally loose it at step 12. It simply doesn’t explain how and more importantly ‘why’, what’s the philosophy behind this process? Why is a Zsphere needed to transfer topology etc. I am one of those guys that simply needs to understand what and why he’s doing certain things. I hate the thought of performing a mere trick.

Maybe it’s too much to ask because the anwser isn’t an simple one.

Ah well I’ll figure it out, thanks…

>>> Importing Topology

You can also bring topology in as an OBJ. The steps for this are below:

  1. Select the Simple Brush in the Tool palette to avoid ZBrush importing one model into another. Press Ok to drop your model to canvas
  2. Press Layer:Clear to clear the document
  3. Press Tool:Import and select OBJ
  4. Select the old model you want to retopologize
  5. Press Tool:SubTool:Append and select the newly imported model that represents new topology
  6. Make sure they line up correctly
  7. Select a ZSphere and draw it on the canvas
  8. Press Tool:Rigging:Select and select the design sculpt from the pop up window. This is the tool with the geometry you want to change.
  9. In the Tool Palette select the model that has the design sculpt and new topology sculpt as SubTools of each other
  10. Make the new topology sculpt the active SubTools by selecting it in the SubTool area.
  11. Select the ZSphere you used earlier
  12. Press Topology:Select and select the previous tool. Since the new topology is the active SubTool it will bring that in instead. Note, right now there is a 25,000 poly limit on the base mesh.
  13. Press Edit Topology
  14. If you want to push or pull points you can clear the mask that is automatically created by pressing Tool:Masking:Clear.
  15. Press Tool:Rigging:Projection
  16. Press Tool:Adaptive Skin: Preview
  17. Adjust Tool:Adaptive Skin:Rez to a higher leve to get more polygons on your new mesh.
#4

ZSpheres are a fairly versatile tool, in terms of the various things you can do with them. You can build primitive base meshes, which is when you see them in their linked sphere forum; and you can also use them to draw new topology on top of a reference mesh, which is when you see the zspheres as simple points connected by edges. Same thing, just a different visual appearance, and different utilities being applied to them for different results. ZSphere’s arent’ used to project anything, they just generate geometry. The projection happens in the SubTool pallet. There, it analizes the difference between your active tool (your new base mesh) and the inactive tool (the old mesh), and projects the detail from the old to the new.

#5

Thanks for the explanation about the Zspheres, I am just used to a more traditional way of modeling so the spheres seem a little alien to me sometimes.
But I understand that when I am using the retopo tools I am creating a new Zsphere for every quad I create.

But as for getting all the details of a high res model back an a new cage model made in Maya. I am still a bit confused about the process, maybe it’s easier to grasp once I’ve tried it.

Thanks

#6

Yeah, if you’re a top-down learner then just dive in and get your hands dirty with it, and it will hopefully make sense. And if you get in to trouble, do a search on ZBC for retopology videos, you’ll find some. NickZ and cannedmushrooms both put videos up often. I’m about to wrap up a retopo job and I’ve been recording it, so I’ll post it today.

#7

Ok that sounds cool, I will surely check it out when your recording is ready and up.

#8

Actually you should look at the videos from the two guys I mentioned. I had problems with my recording and it didn’t come out right.

#9

if you want I can do up a vid tomorrow for you. Just let me know.

#10

Ok too bad it didn’t work with the recording Dustin, I do appreciate the help tho’. :+1:

Yeh allright Goast if you don’t mind doing a vid that would be great!
All help is welcome :stuck_out_tongue: