I've always been able to get great meshes out of .stp files (into .fbx), but have always had issues with the edges of bevels lining up (see attached).

I there is a way to correct this, or is it a limitation of the mesher?

Hi ironsightdesign, that's just a limitation of the mesher. Each surface gets initially meshed independently with a set of quads in its own UV space. That's because the mesher has to deal with all kinds of situations like 2 surfaces that meet up without anything in common in their UV layouts like this for example:



So basically it's the normal case that UV grids won't align with each other naturally. When 2 surfaces meet up that share a lot of common characteristics then it's possible for them to get lined up quads but it's a special case. Can you post your .3dm model file that you show in your screenshot, does it possibly have something cut away from it somewhere?

Note that having quads lined up or not lined up won't really make any difference with regard to rendering.

- Michael

Thanks for the explanaition Michael.

The misaligned quads are not always a problem, except when the points are close together. This can cause banding where the shading is broken, and only can solve it by welding those points together. That can get tedious on large models.

Still, what comes out of the rest of the mesh is far better than any other mesher I've tried.

I can't post the model since it's proprietary, but they are almost always exported as .stp out of Solid Edge. Doesnt have any cutaways.

Hi ironsightdesign, you should only get that kind of banding if you're rendering in some kind of "flat shade" mode where the renderer is not using phong smoothing to make a smooth shaded appearance.

What renderer are you using there?

re:
> Doesnt have any cutaways.

Well I mean if the revolved surface or fillet surfaces are trimmed in any way even with a boolean union instead of a hole. That will then make some surfaces to be longer than others and that will affect the mesh generation too.

I mean like this - usually with a revolve you will get aligned quads:






But once some surfaces are trimmed, some pieces will be longer than others and so get divided up differently than their longer neighboring pieces:





- Michael

Thanks Michael.

I failed to state up front, Im converting Solid Edge models exported in stp, and Im using MoI to convert to fbx to get them into C4D. Im sure part of the problem is that these models were not native to MoI, so the mesh result is less than optimal.

The banding screenshot was the exported fbx in Cinema.

Appreciate all the help/explanations though.

Hi ironsightdesign, do you see the banding only in the realtime viewport display in C4D or do you also see it when doing a rendering?

If you see it in rendering it means that vertex normals are not coming over, double check the import options to make sure any option for importing vertex normals is enabled and also if you still see it maybe try .obj format instead of .fbx.

Your objects should have a normals tag after the import into C4D and you need that to get the best quality shading.

- Michael

Hi Michael,

It's more faceting/phong shading problems more than it is banding. You can see both in the viewport and at render. Though, sometimes you can hide it with a heavy bump/noise material, like casted metal.

It happens when the points of the quads are too close to each other. The only solution I've found is to manually weld the all the points along edges where the quads dont line up after meshing.

Normals are fine.

Hi ironsightdesign, if you can please post an example file I might be able to give you some more detailed information and it would help me to understand the issue and think about what might be done about it.

But in the screenshot you showed above: http://moi3d.com/forum/index.php?webtag=MOI&msg=9458.3 that level of banding should definitely not be seen in a rendering with vertex normals being used.

If you're transforming the objects it could be possible that the vertex normals are being discarded.

It's hard to say anything with certainty without an example to test with over here.

- Michael

Hi ironsightdesign, or maybe it's just some general polygonal artifacts that you don't like? The main way to solve that is to use a higher density mesh when exporting out from MoI.

I've attached an example file, you should get a result like this:






You can also use the "Divide larger than" setting at mesh export time to dice up longer polygons into smaller bits, that should give high quality results without any kind of manual point tweaking needed:





- Michael

Hey Michael.

Reviving this thread to see if there are any plans to help solve this meshing issue.

Still getting shading errors where the mesh points between surfaces are really close.

Hi ironsightdesign,

re:
> Reviving this thread to see if there are any plans to help solve this meshing issue.

No, as described earlier in the thread it's a normal result of how the meshing works.

There's a type of general rendering artifact that you might get when you have long skinny polygons, which it looks like you are getting in the area you have shown.

I would recommend using the "Divide larger than" setting in the meshing options dialog when you export out from MoI, that is also described earlier in this same thread as well:
http://moi3d.com/forum/index.php?webtag=MOI&msg=9458.9

If you are still getting shading problems after using "Divide larger than" to dice up long skinny polygons into more regular sized pieces can you send the model you are having problems with to me at moi@moi3d.com so I can take a look?

- Michael

Thanks Michael

Understand its how it works based on your previous explanations. I should have said "plans to update the meshing process to help this issue".

"Divide larger than" seems to help to localize the shading errors to a smaller area...now it's just finding a balance between fixing these artifacts and polygon counts.

Thanks for the help!

Hi ironsightdesign,

re:
> I should have said "plans to update the meshing process to help this issue".

Sorry no currently there are not any specific plans for that. It's not something that can be done by just an adjustment to the current mesher, it would require designing a different meshing algorithm. That's a very time consuming and difficult task to undertake.

- Michael

Totally understand. This is a relatively small issue that is totally overshadowed by the quality of the rest of the meshing when compared to other CAD meshing tools.