[SOLVED] Weird shading after exporting in .obj

ArsenyZvonar

Hello everyone. I made some low poly building recently to use it in Tabletop Sim as a terrain supply. To be able to use it in TTS I have to export it as .obj with triangulation on (otherwise some of the faces will be transparent). In 3dsMax the model looks good, but when I open it in TTS I get these weird shadows.
Some people recommended me to try to split edges or change shading from smooth to flat, but since I don't have much experience with 3dsMax I'm not really sure how do I do that. Here's what I've tried so far tho:
1. Converting into Patch, selecting all the edges and applying "break"
2. In Editable Poly selecting all the edges and applying "split"
3. Applying Auto Smooth
4. Various combinations of .obj export settings

I have no idea what else can I do and I'd be really grateful if anyone has the solution.
Just in case, here's the .max file and textures: https://drive.google.com/open?id=1KXLgokRlkSJB57TtHoa02f0lmZ84FOxB

TheGabmeister

Not sure, but the mesh might have some broken normals. If nothing really works, try recreating a certain section from scratch, export it and see if the shading is correct.

ArsenyZvonar

TheGabmeister said:

Not sure, but the mesh might have some broken normals. If nothing really works, try recreating a certain section from scratch, export it and see if the shading is correct.

I just tried to delete a poly and cap the hole and somehow it fixed the shading on that exact poly. Although it gonna take a lot of time to do this with every single poly... I still hope there's some other way to fix the model

musashidan

Just had a look at your file. All the selected faces highlighted in blue have no smoothing group assigned. You need to do this before export. And when you export make sure to check 'smoothing groups'. To assign smoothing groups to all faces go to face mode in editable poly>select all faces>go down to the polygon:smoothing groups dropdown and hit Autosmooth(or do it in graphite) The smoothing groups box with the numbered radio buttons is your friend here. Each face or group of faces, when selected, should only have a single button active. If there are multiple the faces have more than 1 group, if none then they have no group.

ArsenyZvonar

musashidan said:

Just had a look at your file. All the selected faces highlighted in blue have no smoothing group assigned. You need to do this before export. And when you export make sure to check 'smoothing groups'. To assign smoothing groups to all faces go to face mode in editable poly>select all faces>go down to the polygon:smoothing groups dropdown and hit Autosmooth(or do it in graphite) The smoothing groups box with the numbered radio buttons is your friend here. Each face or group of faces, when selected, should only have a single button active. If there are multiple the faces have more than 1 group, if none then they have no group.

Just tried that, but it didn't fix it unfortunately. Why I don't think that the smoothing groups are the case is that some of the parts are rendered correctly. For example, while the front door does look weird, the windows look just perfectly. Idk why is it so, each part I was modeling the same way.

musashidan

Must be something on import with whatever that engine is you're using. Apart from the smoothing groups I mentioned your models are clean.

ArsenyZvonar

Ayy, I found the solution! The problem was poorly made UV map. When I checked how the map of those broken polys looked like, I realized that it was just a line. It only had 2 texture coords. When I remade the UV map all those shadows disappeared
How I found it is I compared the file of two different polygons. The one that was laggy and the one that I fixed with the cap tool