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Preserving Subdivisions when retopologizing

ZBrush Usage Questions
#1

Hey all,

I’m currently facing some problems with retopologizing my model, placing the high-res sculpt of my original tool onto a rebuilt lowest subdivision topology from Maya.

As I am going to be putting this character into a game engine, have a low-poly model version is key. However, whenever I re-project the adaptive skin, no matter how many divisions I set the projection slider to, I only ever get one level of division and its the 1.25 million poly division.

So the question is, is there a way of preserving or adapting the lower subdivision levels of a projected high-res model? Or, does anyone know of a way to replace sub-divisions separately?

Thanks for any help ahead of time!

#2

1) Set Tool>Adaptive Skin>Density to the number of levels you want your model to have.
2) If upon turning on the preview you find that your mesh has lower resolution than the source, increase the value of Tool>Topology>PreSubdiv. This causes level 1 of your new topology to have more polygons, which in turn increases the number of polys that the highest level will have.
3) After doing your retopology and projection, use Tool>Adaptive Skin>Make Adaptive skin to finalize the mesh. The resulting model will have a number of levels equal to the Density slider, with the actual density of level 1 being determined by the PreSubdiv slider.

Hope that helps!

#3

Hmm I think maybe I wasn’t clear enough in my description of what I am trying to do.

I created my original mesh in Maya, brought it into Zbrush, divided it up 5 times, and then sculpted it to a point I decided was finished. At this point I then exported the lowest sub-division version to Maya again, where I realized I had some problem faces/vertices and issues with my normals. I fixed these problems in Maya, make very little changes to the overall geometry shape.

What I am now trying to do is to take this low-poly fixed version of my lowest sub-div geometry, and project the previous high-poly mesh onto it. This I have accomplish with ease, however I want to do this while still preserving the low-poly sub-division geometry which I just fixed. I need the lower-poly sub-div geometry so that I can UV map the low-poly version and then apply the high-poly normal map to it and send it to my game engine.

I did not see a presubdiv slider under Adaptive skin, so I assume you were talking about the one under topology. As I am using imported topology the presubdiv slider here is grayed out.

Thanks again for the help

#4

Alright solved the problem.

In case anyone ever runs into this problem:

I was going about this in the completely wrong way. What I ended up doing was taking the new low-poly mesh, dividing it up until it had about the same number of poly’s as my high-poly sculpt.

I then appended the high-poly tool as a sub-tool on the low-poly mesh. Selecting the low poly-mesh in the subtool I then hit SubTool->Project All and my high-poly sculpt was transfered to the new high-poly tool with the repaired low-poly mesh sub-division.

My normal issue caused a problem here though, so I ended up saving a separate copy of my original high-poly sculpt but with the normals flipped using Display Properties->Flip. I loaded them both as subtools on the divided-low-poly mesh and projected them individually while hiding one or the other of the high-poly sculpts.

Minor greebles aside all is well, thanks for you help