HELP 3ds max 2017 obj export smoothing groups

[Anonymous]

When exporting using OBJ to another 3ds package (ie. Marmoset or Substance Painter) it appears to not average the smoothing groups. 

No amount of configuration seems to fix this. This also appears only to be on new meshes created. Any mesh that was working before that exports fine. 

[blakestone]

In your Export Settings change your Faces from 'Quads' to 'Triangles'

[Alfred.DeFlaminis]

Hello @Anonymous and welcome to the community,

Did the post by @blakestone work for you here?   Does the model import back into Max with smoothing groups?   (As a test.)  Would it be possible to attach a simple file (or PM me a link) so I can check it out?  I can also create a private folder if you'd like.

Best Regards,

[Anonymous]

any particular reason why you would have Normals OFF ?

[Alfred.DeFlaminis]

Hello @Anonymous,

I thought that might be the reason myself, but I did a test into substance with it on and without and it worked both times.  It's odd to have smoothing groups without normals though... imho.  But not a dealbreaker in this case it seems.  

Best Regards,

[Alfred.DeFlaminis]

Hello @Anonymous,

I just wanted to follow up here, any progress on this issue?

Best Regards,

[mel_danes]

I have experienced this issue with 3ds max 2017 as well.
The University where I teach uses 2017. Earlier this year assignments I had made in earlier versions of max were importing strange, without smoothing.

I have run some tests using different versions of max ( I have 5 versions installed going back to version 9).

I created a simple poly object in 2017. I then saved it out in 2016 format.
An open, export, import test was done using 3ds max 2016 and 2017.

Step 1.) Open max file.
Step 2.) Export to OBJ using Maya settings.
Step 3.) Import OBJ using Maya settings.

As you can see from the attached images the 2017 mesh has no smoothing applied upon import.
If I import the OBJ exported from 2016 into 2017 it comes through with smoothing intact.

I surmise something is wrong with the export of 2017.

As yet I do not have a work around, for certain assignments I am converting OBJ's into FBX files.

[Alfred.DeFlaminis]

Hello @mel_danes and welcome to the community,

Would you be willing to attach the example file?  I can't seem to reproduce this on my end and I was hoping to figure out where I'm going wrong.  Thanks for that!  Also, which update/service pack are you running?  Thanks!

Best Regards,

[Alfred.DeFlaminis]

Hello @mel_danes,

I just wanted to follow up here, any thoughts on my previous post? Thanks for the update!

Best Regards,

[mel_danes]

I am using 3ds Max 2017 with Service pack 3.

The scene I was using is a baking test scene for teaching students normal baking for rigid body.
The format is for 2016, created in 2017 with backwards compatibility.

Open the scene in both 2016, and 2017.

Select the low object and export it with basic Maya settings as an OBJ.
Then re-import it the obj back into the version that exported it, so 2016 back into 2016 and 2017 back into 2017.

The 2016 export, re-import comes in fine.
The 2017 export, re-import comes in with smoothing removed or broken.

[Alfred.DeFlaminis]

Hello @mel_danes,

I see what you mean when I follow those steps, but it's not the smoothing groups that are incorrect but the normals which are getting Unified.  If you go check the smoothing groups on that imported model it's still working.  The workaround is easy enough, just use the File->Import and make the following change to your import settings, please.

Can you please try that for me?  Thanks!

Best Regards,

[mel_danes]

Thanks for all your work on this.

You are correct it is unifying the normals.

When I use the "Import from Smoothing group" option it fixes it for 2017. In 2016 I did not need to do this, Import from file has worked for years.

The issue is that not all programs have a "Smoothing Group" import option.

By that I mean, when I export and obj from 2016, and bring it back in , without the Smoothing group import, rather I use Import from file, it works fine.
And those OBJ's import into other programs without issue as well.

When I export the geo from 2017, and re-import it I must use from Smoothing group, when in previous versions I did not. Also OBJ's exported from 2017 imported into other software do not maintain normals.

So if I export an obj from 2016 and import it into 3dcoat for painting, the normals are maintained.
If I export an OBJ from 2017 and import it into 3dcoat for painting, the normals are unified.

Why change how normals were stored on export in 2017? It's obvious a change was made, as previous versions did not have this issue.

[Alfred.DeFlaminis]

Hello @mel_danes,

There is a logged issue about incorrect obj normals on export.  It wasn't an intentional change but it is logged in the tracker.  I added a link to this thread in the tracker about it on your behalf.  

Best Regards,

[Alfred.DeFlaminis · Accepted solution]

Hello @mel_danes,

There is a logged issue about incorrect obj normals on export currently and I have added a link to this thread in the tracker.  

The easy workaround is to do the following:

1. Add an Edit Normals Modifier
2. Select all Normals
3. Press Make Explicit
4. Export OBJ.

I tested by reimporting into Max and Maya and it's working fine for me.  Can you please try that?  

If one or more of these posts helped answer your question, please click "Accept as Solution" on the posts that helped you so others in the community can find them easily and thank you for doing so.

Best Regards,

[Alfred.DeFlaminis]

I added an Edit Normals modifier, selected all normals, and pressed "Make Explicit" and that seems to be the key.  Edited previous post.  It seems the Explicit normals is all that is needed, once they are explicit it all works as expected for me.   Interested in your results.  Thanks!

Best Regards,

[Anonymous]

Hi,

  I had the same issue mentioned in this thread. I applied the "Edit Normals" and used "Make Explicit" which actually worked but there is an issue with that. If you happen to take you mesh to Zbrush and then import the hi-poly and try to bake details over the model that you had used edit normals on top, the output Normal map will be something really crazy. I had asked this question on many forums and artist would not understand what actually is happening until i realised the problem was with using "Make Explicit".

   I would then make a copy of my model, use edit normals and then export that copy while the original i would keep for baking later.

[chrisell]

I hate to resurrect a topic from three years ago but this appears to still not be fixed in Max 2022 or Max 2023 - they're still doing some weird vertex normal aggregation on OBJ export. The editNormals hack does seem to work but that's a hell of a workaround especially in a complex scene. Any visibility on when / if this might ever be corrected back to how it was in Max 2016?

[Diffus3d]

This thread is pretty old but I personally use FBX's in substance and have no issues.  Is exporting to a different format a deal breaker?   Seems like the easy workaround here.   I am not sure if the issue was addressed or not, apologies.  

Smoothing groups are not supported by all software and that is not likely to change though. 

Best Regards,

[chrisell]

Just to loop around on this in case it comes up in a google search later (and there's a lot of surplus information in here but it might help someone else out in future):

The source of my issue is/was that I use an unwrapper called RizomUV and it has the capability to overload an OBJ file with extra information that can be retained at the next opening of the OBJ file. Stuff which  is only useful to RizomUV. So OBJ had been my go-to export for unwrapping, while FBX was my general purpose export for things like Substance.

The issue was that the latest version of Rizom correctly respects the normals in the OBJ file where before it was recalculating on import. That led me down the rabbit hole of trying to figure out how to get an OBJ with "proper" normals in it because the imported files became really hard to work with with blended/matched/averaged normals.

After a day of back-and-forth with the Rizom UV helpdesk it became obvious that they now also overload FBX files with that same information - great - I can use FBX now for pushing and pulling stuff in and out of this unwrap tool.

The last hurdle that made me think I still needed OBJ Was that every time I exported a model to FBX, it triangulated certain objects and surfaces, especially thinks like spheres, tubes, etc. (see attachment tube.jpg)

That totally broke the quad editing stuff in Max if I re-imported it. Can't do edge loop selection etc once everything is triangulated.

I checked my FBX export settings over and over and Triangulate was always disabled so I had no idea what was going on. Turns out - in the end - that I also had Preserve Edge Orientation checked and THAT was what was triangulating everything.

Once both Triangulate and Preserve Edge Orientation are turned off in FBX export options (see attachment export.jpg), I get "clean" FBX files that port much more nicely to both RizomUV and Substance Painter.

[Diffus3d]

Good post, lots of good info here.  I too use Rizom and at first had some export issues.  

Best Regards,