ZBrushCentral

.OBJ Import Triangulation problem

ZBrush Usage Questions
#1

When I import an object (.obj) as a tool (from 3D Max, where I’ve created the mesh to work from), I often get very strange artifacts when I use projection master and import my own alpha to create patterns on the mesh. This problem aslo exists when I import an alpha as a stencil to work from.

The mesh looks great when in projection master, but when I pickup the mesh and exit PM, the triangulation of the imported .OBJ file creates horrible jaggies and distortions, ruining my efforts.

When I create an original mesh within ZBrush using Zspheres, it does not do this, and works fine. Unfortunately, Zspheres is not an easy way to model what I need (not very good with it yet).

This triangulation problem exists even when I divide the object up to a million poly’s.

My question is this: Is there a way to turn off triangulation - either when exporting from Max or after importing to ZBrush - so that the mesh is only horizontal and vertical polygons with no triangulation?

#2

Initially, I had written Metaballs instead of Zspheres. Metaballs is a similar tool in TrueSpace, not ZBrush. Duh. Sorry for the confusion, I had a brain cramp.

Now that thats settled, any help would be appreciated. This problem is driving me nuts!

#3

I can’t help with Max settings, but I can probably help with ZBrush.

When you drop your model to the canvas it is smoothed by default. When you pick the model up again, it’s unsmoothed. This causes the texture to wrap differently and no longer look right.

Try turning off Quick 3D Edit and setting Tool>Display Properties>DSmooth to 1. Does the texture look good again?

Now the six million dollar question is, which way will your model be rendered in your application? If it’s going to be smoothed then you should continue with the above advice. If it’s not going to be smoothed then simply set the DSmooth value to .01 before you drop the model in Projection Master. This will prevent it from being smoothed so that what you see when painting will be what you see when it’s picked up.

#4

Thanks so much for your help. I will try your ideas.

One of the reasons I’m having some difficulty here is that I’m using PM to affect the surface geometry of the meshes for rapid prototyping, not really for rendering purposes (I am designing hardware products for kitchens and baths for Home Depot, Lowe’s and Target stores).

In using PM this way, any problems visible in the geometry will also be produced when the model is output as an .SLA, .IGES or .STL file. When Ive created the meshes within Zbrush, this is not a problem. Unfortunately, ZBrush modeling (as I understand it) does not allow for the precision or measuring of the mesh geometry that I require in order to meet engineering standards for the products (for example, how far apart screw holes must be to mount the item correctly). So, Im stuck modeling in an outside app. Right now, I’m using various combinations of TrueSpace 6.6 (for easy rendering and lighting), Max, Inventor 10 for modeling the basic meshes.

Any further advice, based on this new input, would be welcome.

#5

http://www.andrew.cmu.edu/user/beiy/tutorials/quadrangulate.html