Substance Painter 2019.2 Smoothing Errors?

Amank679

Hi All,

I'm in the process of baking on my Gun model but came across an issue that I haven't been able to fix yet.  The top pieces of the gun here are completely hard surfaces with all hard edges. For whatever reason, when I  import it to Substance Painter it smooths certain areas.

I've gone back and hardened edges again, cleaned up the model and further optimized the UVs, but I'm still coming across this issue. I also went ahead and updated to the latest version Painter in the hopes it was a version bug, but the issue still exists.

Lastly, I tried the Game Export setting in Maya instead of the traditional export selection option with smoothing groups disabled. This didn't help either.

I've attached a few images below which showcase this issue.

Not sure what could be causing the problem. Please let me know your thoughts.

Thanks in advance!

Ashervisalis

This is pre-bake, right?

Select your model in Maya, then try going to Mesh Display > Set to Face.
I'm seeing some ngons on your site/arch, I'd fix those.

See if that helps!

Amank679

Ashervisalis said:

This is pre-bake, right?

Select your model in Maya, then try going to Mesh Display > Set to Face.
I'm seeing some ngons on your site/arch, I'd fix those.

See if that helps!

That, unfortunately, didn't work. I did import the model into Marmoset Toolbag and the error didn't appear. I'm going back and cleaning up the model now.

CheeseOnToast

Can you upload your model so I can take a look at it? OBJ or FBX for preference.

Amank679

@CheeseOnToast

Hi, sorry for the late reply!  Also, I seem to be getting some AO artifacts that I've been trying to fix for a while now. I've cleaned up the model thoroughly and played around with different settings, but still have the issue.

 

As far as the Model goes, I've exploded the model to prevent AO from leaking onto other parts. Also, Most, if not all my Normal detail on the model will be sculpted via Zbrush, so my High poly model is just a duplicate of the low poly without any additional detail.

I'm not able to attach an FBX file so I've attached a link to a Google Drive folder where the file can be downloaded:

https://drive.google.com/drive/folders/1zlLehbTHwfh_KuTMCcz4kHzkUAEV2CFi?usp=sharing

CheeseOnToast

@Amank679

Would you mind re-exporting as an OBj if possible? I'm getting some import issues in both an old version of Maya and Blender 2.8. I want to rule out any FBX weirdness.

I got it to work by importing into blender then re-exporting the fbx. Starting a new Painter scene and importing the model gives an error concerning invalid normals, which painter then re-calculates.

The model itself needs a bit of work. For example, on the rails the current triangulation results in a ton of extremely long and thin triangles all converging at a single point. They're so close together that the edges are nearly overlapping.

Anyway, here it is in Painter after the re-export.

Amank679

CheeseOnToast said:

@Amank679

Would you mind re-exporting as an OBj if possible? I'm getting some import issues in both an old version of Maya and Blender 2.8. I want to rule out any FBX weirdness.

I got it to work by importing into blender then re-exporting the fbx. Starting a new Painter scene and importing the model gives an error concerning invalid normals, which painter then re-calculates.

The model itself needs a bit of work. For example, on the rails the current triangulation results in a ton of extremely long and thin triangles all converging at a single point. They're so close together that the edges are nearly overlapping.

Anyway, here it is in Painter after the re-export.

I've updated the drive link with the OBJ file. Also. Those tris are quite thin, but they aren't overlapping. Can really thin polygons cause baking errors?

CheeseOnToast

They're bad for several reasons. It might seem like it's economical to have as few tris as possible, but the cost to render skinny tris outweighs the cost in verts of cleaner topology. There was a very clear breakdown on Simon Trümpler's excellent blog here https://simonschreibt.de/

I can't seem to find it there any more. Hopefully someone will have a link to it. As a VERY general rule of thumb, if a triangle's longest edge is more than eight times the length of its shortest edge, it's too thin. They're unavoidable sometimes, but you should try to minimise them.

Edit: Found the reference I mentioned above. It's here : https://simonschreibt.de/gat/renderhell/

Amank679

CheeseOnToast said:

They're bad for several reasons. It might seem like it's economical to have as few tris as possible, but the cost to render skinny tris outweighs the cost in verts of cleaner topology. There was a very clear breakdown on Simon Trümpler's excellent blog here https://simonschreibt.de/

I can't seem to find it there any more. Hopefully someone will have a link to it. As a VERY general rule of thumb, if a triangle's longest edge is more than eight times the length of its shortest edge, it's too thin. They're unavoidable sometimes, but you should try to minimise them.

Edit: Found the reference I mentioned above. It's here : https://simonschreibt.de/gat/renderhell/

As for those unavoidable circumstances, would you say its more convenient to split thinner tris up into smaller polys? Even if it adds to the poly count?

CheeseOnToast

Yes, in general. Don't go crazy - you don't need to tun every bevelled edge into smaller quads. A simple example might be a gun barrel. A long cylinder might render more efficiently chopped into 2 or more sections.

Amank679

CheeseOnToast said:

Yes, in general. Don't go crazy - you don't need to tun every bevelled edge into smaller quads. A simple example might be a gun barrel. A long cylinder might render more efficiently chopped into 2 or more sections.

Ok, awesome! Thanks for the feedback!

CheeseOnToast

OK, took some time to look at your mesh. Aside from the triangles I mentioned previously, there's some other issues. First, you have a couple of bits of non-manifold geometry where you've merged vertices from the tube things to the main body of the gun.

Secondly, you have some hard edges but with no corresponding split in the UVs. In the image below, I've marked your UV border edges with thicker lines.

Finally, I had the same problem as you exporting your original mesh. I fixed it by doing Normals>Unlock normals, softened all edges, then ran a script I have which turns all UV borders into hard edges (you could do this manually, I just wanted to quickly make sure vert normals were being preserved correctly). It imports into Substance Painter properly after that. Here's my FBX geometry settings. You really don't need to do anything special here.

Amank679

So I've been cleaning up the model further and have got this as the end result. Not sure if I can get the tris any bigger here

Also, I'm not quite sure what unlock normals actually does.

As for your export settings, Wouldn't having smooth mesh checked cause smoothing when importing to Substance?

Also, as a side note, do the smoothing groups make any significant difference in smoothing on the model?

Taylor Brown

Is there any particular reason those grooves cant be floating geo?

Amank679

Taylor Brown said:

Is there any particular reason those grooves cant be floating geo?

By floating, do you mean as high poly bakes?

Taylor Brown

No, sorry, I'm wondering why you've even bothered connecting those ridged areas rather than have them disconnected and sitting on the surface.

Amank679

Taylor Brown said:

No, sorry, I'm wondering why you've even bothered connecting those ridged areas rather than have them disconnected and sitting on the surface.

With guns and most assets, the general flow of the model should be continuous. Meaning it's best to have as few parts as possible. The parts that would need to be animated or would add too many crazy polygons to attach them can be left detached. At least, it's what I've been told by other artists and seen on other models.

Also, I did tweak the model a bit more here: