Maya where can I find help on .obj export settings?

malcolm

I'm looking for a description of the checkboxes in the .obj export settings in Maya? Some of them are obvious, but some are not. Does anyone know?
Groups:
Point groups:
Materials:
Smoothing:
Normals:

Eric Chadwick

Some here
https://polycount.com/discussion/149754/what-is-point-groups-in-obj-export-settings
and here
https://en.wikipedia.org/wiki/Wavefront_.obj_file#Material_template_library
and especially here
http://www.martinreddy.net/gfx/3d/OBJ.spec

malcolm

Good grief, that's complex.

Eric Chadwick

Short of if is Groups define materials on sets of faces.

Materials are pretty simple, old fashioned diffuse/spec. Smoothing is hard edges. Normals is custom vertex normals.

Eric Chadwick

I'm not a Maya guy, so I'm not up on the specifics of their exporter. Some testing is probably in order here.

malcolm

the most kryptic is "smoothing" which I think is incorrectly labelled and should be smoothing groups, but I'd really like to confirm with some Autodesk documentation which I can't find.

Eric Chadwick

Open the last link and do a search for "smoothing", I thought it was pretty well explained. 

malcolm

That's a bit technical, but it looks like smoothing does mean smoothing groups and is not needed if you have vertex normals. Maybe programs other than Maya make use of the smoothing groups. I think Unreal still gives a warning if you don't have smoothing groups, even tough they're not needed if you have normals on your mesh.

Eric Chadwick

I'd recommend just trying it out with simple cubes. Best way to learn.

malcolm

I did, it's unclear. I even diffed the files in notepad++ with point groups on/off and the file generated identical, it's very cryptic. Some are obvious, this is what I've deduced.

Groups:

-On separate objects in the scene

-Off everything combined into one object

Point groups:

-On no idea?

-Off no idea?

Materials:

-On mat id's saved to a separate file

-Off default material applied to everything

Smoothing:

-On include smoothing group info in the file

-Off no smoothing group info in the file

Normals:

-On include vertex normals in the file

-Off no vertex normals in the file