3DS Max Exporting Smoothing groups with Obj

bob3636

Hello guys is there any way to retain SG in export (using the gw obj exporter) ?
Seems it doesn't let me export in any way having both normals and smoothing groups options selected.
The only way i can export them is by using triangles instead of quads (which i don't want)
Doeas anyone has a fix for this?
I'm in max 2017 btw

Farfarer

No, the obj file format doesn't support smoothing groups. Only explicit vertex normals (i.e. the visual result of smoothing groups).

bob3636

is there a way to bake these normals? o something like that in order to export them basically?

Axi5

It's been a while since I've used Max but you might be able to drop an "Edit Normals" modifier on top, select all of the normals in the viewport and then hit "Make Explicit" or something to that effect.

musashidan

Curious why you're not using .fbx?

bob3636

because some applications does not support fbx and i was curios if i could retain SGs, ty guys  i'll do some tests

thomasp

if you don't care about splitting the geometry then you can select by smoothing group before export and detach to separate elements prior to export.

Butthair

I'm lost a bit here...

If I'm exporting to a non-Zbrush software, I will use Maya preset each time. And when I load those models into another software (maya, xnormal) or engine, the "smoothing groups" are still there.

No, the obj file format doesn't support smoothing groups. Only explicit vertex normals (i.e. the visual result of smoothing groups).

Expanding on this - Smoothing Groups are a term for Max. Maya doesn't refer to them this way, instead they are soft/hard edges. So I'm lost, are you specifically trying to keep SG info or retain hard/soft edge smoothing on the model from max to another software?

bob3636

Yeah i mean i call them Smoothing grps but as a long time maya user too i mean the softness and hardness of the edges. In Maya is really that simple.
That said i cannot preserve tje edge quality, even tried presets, and even simply exporting and reimporting in max i loose the edges quality i get an entirely soft mesh
 Don't know why, seems really like is not supported the exporting for obj files, i'll try your settigs but i'm sure i have already tried.
Cheers!

Noors

Max .obj retains smoothing groups, atleast on 2016.
I guess they are defined following the "s"  lines inside the obj file, if you open it with a text editor.

- normals => export all vertex normals as explicit, no SG
"vn" inside the obj file

- smoothing group => export pure SG. All explicit(edited)normals are reseted.
block starting with "s" inside the obj file

-both => all normals are set to explicit, but SG are still retained. If you reset the explicit normals, you get the SG back.

You can't import partly SG and partly explicit normals in max. It's a limitation of the importer, not that you'd really need that tho.

Now are obj SG correctly interpreted by Maya/whatever importer is another story. But Max deals correctly with them.

musashidan

bob3636 said:

Yeah i mean i call them Smoothing grps but as a long time maya user too i mean the softness and hardness of the edges. In Maya is really that simple.

Max has SGs and hard/soft edges (same as Maya) So if you don't like using SGs you can always just use the Maya workflow.

Butthair

What are you importing to?
Is that where the problem is occuring only?
Can you export from and back into max or maya?

bob3636

i simply try to export form max and reimport back, and SGs get lost.
@musashidan  yeah but im not sure that hard soft edge are fully supported... For exmple whe i use them and try the "select hard edges" tool in graphite modeling t doesn't select them. I don't know

Butthair

It might have been that the model had some strange bug in it and exporting and reimporting might have cleaned. Models get issues like this where obj export is a way to clean them.
If you've reimported it, try setting SGs and export then reimport again. Make sure that the first reimport is in a fresh clean max scene.
Also try giving the model an Edit Poly modifier, this will clear any custom normal shading.

Since at this point it's stabs in the dark, shoot the model over, I'll take a check to see if it's your max or the model.
And as a side note, I can export as OBJ with SGs on my machine.