I’m making a figure that I would like to work in both Poser and Daz Studio. The object looks fine in Modo, Lightwave, Zbrush, Maya and Poser, but Daz Studio insists that two of the polygons have backward normals. If I reverse the normals of these polygons to appease Daz Studio, Poser (and apparently every other 3D software in existence) sees backward polygons where I “corrected” the geometry. Can’t we all just get along? Is there a secret for getting Daz Studio to agree with the rest of the world about what constitutes a forward normal?

Ok, here is one solution. Just keep rebuilding the problem area until you find a polygon configuration that both programs will interpret as normal forward: Not too painful, provided that you have a modeler that lets you modify the geometry without destroying the uv maps. 

can you split the poly in 2 ? that usualy fixes these hickups..

that wont destroy your uvmap btw ... but you might need to ad a mat zone to the new polys

Chris

I deleted a few polygons around the trouble spot and then closed the gap with a different order of polygons. Modo filled in the blanks in the uv map and assigned the right material and part name to the new polys. Maybe splitting the polygon would be a quicker fix, but I was trying to avoid creating tris. (Not that it worked.)

If you made it in Modo ..it can be MODO that made the error..

I have them too ... OBJ files exported from Modo that have stray polys that does not align with the rest ...

I used a OBJ exporter script on windows that fixed the problem perfect ..

Now im on a MAC and no such luck with a good script ..

MODO => OBJ export sucks a bit .. so maybe thats your problem ..

Chris

Are you sure they were simply reversed? DS doesn't like triangles that have an extra vertex along one edge, and tends to render them black, but flipping the geometry shouldn't have fixed that. I believe, though I'm not certain, that Poser ignores the normals (vn lines) in the OBJ and DS uses them if present, but that may be wrong or may have been true once but no longer.

Poser does ignore the vn lines.  It calculates normals on its own, using the 'winding order' of each facet. It's best to leave out the vn lines in an OBJ intended for Poser and Daz.  An OBJ without those normal values will work in both.

Usually a few bad facets have the wrong winding order (clockwise as seen from outside, which makes the facet point inward by Poser's standards), and I've found that UVmapper will often fix this without any special action.  Load the OBJ in UVmapper, and directly save it with the "Don't export normals" box checked.  The result will be vn-less and usually correct.

make sure you DO NOT check the import option to fix normals, its more trouble than its worth in my opinion. 

I have them too ... OBJ files exported from Modo that have stray polys that does not align with the rest ...

The actual obj. was exported from Lightwave.

Are you sure they were simply reversed? DS doesn't like triangles that have an extra vertex along one edge, and tends to render them black, but flipping the geometry shouldn't have fixed that.

The problem areas actually were triangles with an extra vertex along an edge*.* Flipping the polygons solved the problem on one side of the symetrical object but not the other*.* At that point I deleted the bad polygons and rebuilt them. (Still triangles with an extra vertex.) This resulted in the problem areas migrating to nearby polygons.

A triangle with an extra vertex along one side is a good way to go from high poly to lower poly. I still have some of those and Daz Studio can handle them, but should I avoid this topology in the future?

Load the OBJ in UVmapper, and directly save it with the "Don't export normals" box checked.  The result will be vn-less and usually correct.

Thanks for the suggestion. *

Note the similar conjunctions of faces circled in green that do not display the error you've described.

Slightly move the vertexes on the non-convex faces to create convex faces and the artifacts will disappear.

Quote - The problem areas actually were triangles with an extra vertex along an edge*.* Flipping the polygons solved the problem on one side of the symetrical object but not the other*.* At that point I deleted the bad polygons and rebuilt them. (Still triangles with an extra vertex.) This resulted in the problem areas migrating to nearby polygons. A triangle with an extra vertex along one side is a good way to go from high poly to lower poly. I still have some of those and Daz Studio can handle them, but should I avoid this topology in the future?

If you can avoid them, or stretch them into a more kite-like shape as in the examples bob1965 circles, it should help. DS (or 3Delight) seems to be fussy about this.

A "triangle with an extra vertex" is usually called a quad :biggrin: and not even Studio or Poser have problems with those! I would be more suspicious of the neighbouring 5-vertices stars as source of problems.

I think that Modo spoils people; I have seen a tutorial in which the tutor created a face with 30/40 edges and the render was nonetheless perfect. Don't assume that low end stuff like Poser or Studio share the same amount of badass-ness.

No, the described problem is caused by the collapsed edges shown in the faces circled with red, the "triangles with an extra vertice".

This particular issue can be replicated at will.

The 5 point poles you mention are the source of different problems that evidence when sculpting in ZBrush, using Faceshop, morphing with magnets, etc.