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Zbrush to 3D Coat Retopology - Symmetry.


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I was wondering if anyone could offer me some advice about how to get to grips with 3D Coat for retopology.

I bought the program a couple of weeks ago, to speed up my retopology and UV workflow. The UV part of the program has been very easy to use and I think that I'll get to grips with it quite soon. However, I am having trouble getting up to speed with retopology using the program.

On the face of it the 3D Coat seems brilliant for retopology. The tools that I have worked out how to use seem quite straight forward. However, I am encountering issues that are really slowing me down. It might be useful here to explain what I'm trying to do and the workflow that I'm trying to develop.  My primary 3D software is Zbrush and 3dsMax and this is where I'd have done any retopology in the past. I've been importing high res meshes in for reference and then trying to edit a low res Zremesh - the areas that I want to retopo are the face, ears and hands.

I usually manage to rebuild the detail that I need for these areas, but I'm encountering some issues with symmetry. The main concern is that faces, edges or vertices that overlap the line of symmetry which can either not be welded or have overlapping faces and edges. This will obviously cause the mesh seams to split when subdividing it back in Zbrush. I've managed to clean up meshes with messy symmetry in 3dsMax - but instead of speeding me up is adding another layer of work. Is there something that I can do about this?

Also, I've struggled to fully get to grips with symmetry in 3D Coat. There is virtual symmetry and actual symmetry. Whilst this concept is easy to come to terms with when creating entirely new geometry, it's harder to understand when working on an imported retopo mesh. When I import the mesh that I want to edit and then turn on symmetry (with virtual symmetry) - I get a pale preview of the other side, but if I turn off virtual symmetry the actual geometry still exists. So I'm not sure if this is causing me problems - my mesh may look finished and clean but in fact its got other unseen hidden geometry. It would be nice to simply select and delete the polys on the side that I will not need, but this doesn't appear to be an easy process. The selection tool in 3D Coat appears to work like a brush, with no selection marquee. Getting rid of a whole side of geometry that you don't need would be fast to do in either Zbrush or 3dsMax. Is there a quick way to do this inside 3D Coat? Would I be better for me to import only half of the mesh for retopology?

My primary concern is about the main line of symmetry running down the middle of the mesh. Instead of seeing a simple seam there can be a confusing zig zag of edges or overlapping faces. In 3dsMax, you can delete half your model set the transform modifier to Slice Along Mirror and Weld Seams to avoid problems. Are there settings that offer this option in 3D Coat?

On the whole, I'm impressed with the program. However, I do wish that there were more quick start tutorials about how to use the 3D Coat. Many of the tutorials go in to detail about areas of the program that I'm unlikely to use at the moment and many of them seem to be from earlier versions. It would be nice if there were some more recent tutorials - like myself, a great many of your users must have come to this program from Zbrush just for retopology and UVs. I ended up resubbing to PluralSight hoping that they'd have some decent tutorials to follow, They are okay, but don't address the issues that are concerning me.

Anyway, I will keep watching the video tutorials on this site to see if I can get the answers that I need - though it is quite time consuming and a bit hit and miss. So if anyone could offer some advice about how to make progress with symmetry in 3D Coat then I'll be grateful


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Question Number 1: Importing a high polygon reference mesh for creating the low polygon mesh in the retopo room.

No need to use virtual symmetry. Real symmetry will create the other side of the axis as long as you have perfect symmetry.

I will explain how to keep perfect symmetry with no overlapping polygons. 

Symmetry turned on but not virtual symmetry. Have the symmetry plane showing also.

When creating your polygons along the symmetry line, first be in ortho mode. Now zoom in closer to the mesh. You will see the two white dots, one will be inside your cursor. Line these up over each other, they do not need to be perfectly aligned but pretty close. Click to weld the the two polygons that will be created, no overlapping will happen. White dots shown in picture. The white dots are the key here.

Also I keep my mirror snapping at about 10%, that is located in the upper tool bar. 


Of course you can use virtual symmetry if you so wish, so the below explains.

You can do the above with virtual symmetry turned on but the same rule applies. Under the retopo menu you must select  "Apply symmetry to current layer or Apply symmetry to all layers" to turn your virtual symmetry to real geometry. Turn off virtual symmetry to see your true polygons. Virtual symmetry is not user proof being a retopo tool and a user can create the overlapping polygons. 


Imported mesh or fixing symmetry line problems your last question.

If you need to delete half the model to create a mirrored half where the center line is perfectly line up that is very possible. Make sure you are in faces mode (upper tool bar). Use the rectangle lasso from the Epanel (E key) to draw over the polygon faces that need deleting, delete them.  Now select edges in the upper tool bar. select one edge on the outer edge and then press "L" to select all the edges. Turn on symmetry and Use the transform tool to drag all the outer polygon edges over to the symmetry line. They will snap to the symmetry line. Just drag the transform gizmo a ways pass the symmetry line to make sure they get snapped. Deselect the edges and use the symmetry tool ( left tool bar) to copy the polygons to the another side. 

You can do the same without symmetry turned on, just drag all the polygons so that one edge of all the polygons is a little ways over the symmetry line, then turn on real and virtual symmetry and then apply as real polygons, Turn off virtual symmetry. Though your polygons have been moved a little to the mirrored side, the created polygons will be symmetrical with no overlaps...

I written this the best I could but also would be happy to show you through Skype if you use it. Send me a pm if you so desire. The above methods are fast once you know them.

Also recommend testing on a simple model to get a feel of how these methods work.


white dots.jpg



Edited by digman
errors in writing
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Thanks for taking the time to answer my questions. I'm still messing around with the program and kind of getting there with trial and error. I had a go at a complete figure retopo which took a while but I learnt a lot - no mesh errors when reimported back into Zbrush. I've also watched a lot more of the retopo tutorials from the link provided by AbnRanger so I have a better idea of how powerful the retopo room and all its tools are. Also thanks Digman for taking the time to make detailed description with tips - I'll take a much closer look at them tomorrow to see if I can apply all the advice that you've offered.

I can really see that once I get familiar with the program it should be super fast to get retopo done using 3D Coat - most of the work that I want to do is for a simple clean accurate mesh that I can re-sculpt back in Zbrush . I'm pretty sure that I'm going to stumble quite a bit to understand all of the concepts - 3D Coat is a much deeper program than I imagined - so I'm grateful that you've been kind enough to offer me assistance.

So thanks once again!

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