Thank You, Michael...

If that is the case, then it won't help me much. I was under the impression that the format would deal with triangles a bit differently, i.e., not necessarily straight lines. From your description, I'll search for something else. If the Shapeways prototype comes out as smooth as the old ZCorp SLA epoxy hardened finish, I'll be happy. Unfortunately, it was too brittle for foundry casting. I should receive the 3D printed output today via USPS. I'm anxious to see the results. Regards...Bob

Hi Bob,

> I was under the impression that the format would deal with triangles a bit
> differently, i.e., not necessarily straight lines.

Can you remember where you saw that information?

I've read through the 3MF spec from here:
http://3mf.io/wp-content/uploads/2015/04/3MFcoreSpec_1.0.1.pdf

and the only mention of geometry that I've found in there is about triangles made up of 3 straight sides.


One of the things which I found confusing about 3MF initially was their main web page shows a sub-d smoothed model with quads in it on as their background graphic, so I read through the spec expecting to find something related to that in it but there was nothing mentioned. So there's a bit of a disconnect there between their fancy background graphic and what the actual spec allows for.

- Michael

The now obsolete AMF format did have support for curved triangles.

I don't think it would have improved the actual 3d print though. It would have made the files smaller and improved the time for data exchange.