Because your mesh has n-gons. Since your object is a simple revolved surface, try exporting with the quad/tri option...

jonah

Hi Tony - if you turn on vertices in Modo and examine the points in those areas you should see that a couple of the polygons in that area got created as 5 point n-gons instead of as 4 point simple quads.

It looks like you may have 2 5-point n-gons in there.

They will look something like this:



Notice the extra point along the side there with the red arrow pointing at it?


A few of these can be created sometimes right now in the seam area where a closed surface like a cylinder has its ends sealed together.

I will be looking at tuning this up in v2 pretty soon here to avoid making those.

But typically there should only be a small number of them.

- Michael

Thanks for the info guys. There weren't too many of these and didn't take too long to clean up but I would have preferred not to of course.

JB - Quads and tris had problems which were clear in the preview so I went with the ngons. I really wanted quads, and it looked like quads so I thought I'd done it :-)





Michael, I look forward to the tune up on this.