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3ds max primitive to zbrush problem

ZBrush Usage Questions
#1

Hi all,

Not sure if this is a stupid question or not, but I’ve been trying to sort it out for a while now and getting frustrated so thought I’d ask here.

New to Zbrush so just wanting to do a simple test.

I’m using 3ds max 2008 and Zbrush 3.1. My problem is that when I make a normal sphere in Max (not changing any settings) and then export it as an .OBJ, importing it in Zbrush (using import tool, then drawing it on the canvas) it looks like the sphere I made. But then when I go to edit mode and subdivide it (ctrl -D) I get holes in the poles.

Also, when I try to enter ZMapper it says I got mulitiple UV groups. Checking with Frame > Polygroups > Uv groups indeed confirms this. Things seem to go wrong with the seams or something. (also happens on other Max primitive btw)

I’ve seen a tutorials (movie) from a guys in Max 8 doing all the above steps and not running into any of the issues I have.

Could you guys please tell me if I’m doing something wrong, and if so what should I do. Thank you very much.

#2

The holes that you’re getting at the poles would be caused by unwelded points. When you subdivide a mesh, it smooths. This causes a contraction of the mesh, and unwelded points will pull away from each other. Check your export settings in Max.

For the other issue, you would need to assign UV’s to the model. You can do this in Max before exporting. Just make sure that all the UV’s are in the 0,0 to 1,1 space. Or in ZBrush you can apply a blank texture to the model and then press Tool>Texture>GUVTiles to map the model. If you’re going to be creating a tangent normal map, though, you should do the UV’s in another app due to the math behind this map type. Tangent maps need to have the UV seams hidden as much as possible.

#3

This might night be your best solution, but I found that when you import a sphere from Maya to Zbrush you get the same results. The sphere is composed of quads until the last set of faces on both poles. These last set of faces are triangles because they’re sharing one vertex which happens to be the pole of the sphere.

I got around these pole holes by deleting all of the triangle faces and leaving it hollow. I left it hollow because it would end up leaving me with quad faces, which Zbrush prefers. I then imported the mesh into Zbrush and then divide the tesselation. You will notice that there are still holes in the mesh, but from here you can create a large enough brush and pinch, smooth and flatten the holes until they dissapear. This should be a good quick method around the holes, while still keeping a proper UV layout.

#4

create either a box in MAX with XYZ edges on it…and add the spheraphy (spelling) modifier to it…that will give you a complete quad sphere.

or just load up the PolySphere mesh inside Zbrush…you have to go to load tool…it’s in the default Ztool folder