Hi Michael,

No the flip/flip dont resolve the problem.
Something weird is that the ngone that looks like a triangle has 6 points. In fact it's a triangle, but the vertices are duplicated. I can merge the vertices in modo (with 0 distance radius), and it resolves the problem.

I'm wondering if its maybe a side effect of the special exporter for creating this famous wireframe hack.

Hi PaQ,

> No the flip/flip dont resolve the problem.

What about if you go and look at it from the other side, can you see it on the other side or is missing from both sides?

Missing from both sides most likely means triangulation failure due to some degenerate too-close-together points in the n-gon.


> I'm wondering if its maybe a side effect of the special
> exporter for creating this famous wireframe hack.

No, it shouldn't be related to that - that segment generator thing didn't change anything about how mesh vertices are created.

You've just got a case here where the points from the trimming edge ended up close to the points from the untrimmed underlying surface refinement but not quite close enough for them to be get merged into a single point. It's probably something I could tune up a bit, but it's a pretty delicate area because glomming points together too much can mess things up also.

- Michael

»» What about if you go and look at it from the other side, can you see it on the other side or is missing from both sides?
Yup, the poly is missing in the booth side.


Ok I have replace moi_lib.dll with the original one, and restore the .ini. (sorry you reply too fast :))

The problem is still there ... there are 72 overlapping vertex in the object. After the 0 radius merging, and a double flip, only one triangle if still missing.
Looks like the model generate a lot of small radius overlapping vertex. (an other merge with 0.1 mm radius remove an other 138 vertices :S)

If they're exactly stacked on top of each other, that's something that I could probably be able to tune up better without any bad side effects though.

- Michael

»» If they're exactly stacked on top of each other, that's something that I could probably be able to tune up better without any bad side effects though.

Well it's up to you, I have to admit it's probably not the kind of geometry I'll produce normally, I was trying to bug track something different in modo :)

> Looks like the model generate a lot of small radius
> overlapping vertex.

There's basically two kinds of refinement that happens when the mesh gets created - the underlying surface gets broken down into quads, and then apart from that trim curves get broken down into some little edges as well.

In the pieces here where you've got a surface cut at like a 45 degree angle, some of the vertices from underlying surface quad refinement are really close to the vertices from the trim edge refinement - something along those lines anyway.

- Michael

Hi PaQ,

> Well it's up to you, I have to admit it's probably not the
> kind of geometry I'll produce normally,

Well, if I can produce better mesh output without any bad side effects from a change, then I'd be all for digging into it.

But if your immediate problem is solved by merging vertices in Modo, I'll probably put it on my list of stuff instead of worrying about it right this moment.

Does the merging step in Modo have any bad side effects like throwing out vertex normals?

- Michael

Hi Michael,

Yes I did a final test, merging the model at 100mu, and everything looks right in one step.
So the problem is solved from my side.