Baking Problem in SP (Modelled in Max)

michaelarby

Hi guys. I have a problem. Experienced Max user here, and I was making a little stick grenade, just as a portfolio piece. Trouble is, I cannot for the life of me ge it to bake properly. Shown below are the low poly and high poly, along with the object names. 

The head section of the high poly has been split into multiple objects, but all named as head_high (this I believe should be fine for the bake?). Most of the hp is just chamfering of edges. nothing too fancy. 

Using Max 2021, and an older version of SP. 

Problem is, I keep getting crappy bakes in substance, like below:

I've made sure both hi and low are exported an the origin point and overlap perfectly in max. 

I've tried resetting xform on all objects in max

I've Converted all objects to editable mesh, then back to editable poly. 

I've unified normals on every object, both high and low. 

I've tried baking Match method to 'always' instead of 'by mesh name' 

I've tried using the low poly mesh with smoothing groups applied, and no smoothing groups. 

I've baked dozens of objects in SP before, never had trouble like this. I cant think, what simple, stupid thing am I missing. Would appreciate any help. This is an older model i started a few years back and just wanted to finish it - could it just be corrupted somehow?

 Cheers

EDIT - EXTRA INFO:

File was exported as fbx, both the low and the High. 

UV Map is shown here:

I have attached my high and low poly fbx files, as well as the 3ds max file. the max file might be slightly different to the fbx as i have tinkered with it slightly since!

Eric Chadwick

What do the UVs look like in Max? Are they all welded, and all facing forward?

What does a regular uv checker grid look like on the lowpoly (with letters and numbers, something like this: http://wiki.polycount.com/wiki/File:Uvrefmap_grid_small.jpg) 

A couple things to try:

Make sure the verts aren't split:
Vertex Weld modifier, tweak the threshold.

Remove all edited normals:
Edit Normals modifier on the low, "Normal" sub-object mode, select all, hit the Reset button.
Collapse the stack.
Smooth modifier, Auto Smooth.

What file format are you exporting from Max? If FBX, have you tried a different version of the exporter? Or better yet, try OBJ instead.

Fabi_G

Hi! Could you share the meshes, so users can reproduce the issue on their end? If you don't want to share the whole object, you could isolate a part the issue can be reproduced with. A zipped archive can be directly attached to a post.

michaelarby

Fabi_G said:

Hi! Could you share the meshes, so users can reproduce the issue on their end? If you don't want to share the whole object, you could isolate a part the issue can be reproduced with. A zipped archive can be directly attached to a post.

Thanks FAbi - I have attached the 3ds max file, as well as the fbx files of the high and low poly to the original post. 

michaelarby

Eric Chadwick said:

What do the UVs look like in Max? Are they all welded, and all facing forward?

What does a regular uv checker grid look like on the lowpoly (with letters and numbers, something like this: http://wiki.polycount.com/wiki/File:Uvrefmap_grid_small.jpg) 

A couple things to try:

Make sure the verts aren't split:
Vertex Weld modifier, tweak the threshold.

Remove all edited normals:
Edit Normals modifier on the low, "Normal" sub-object mode, select all, hit the Reset button.
Collapse the stack.
Smooth modifier, Auto Smooth.

What file format are you exporting from Max? If FBX, have you tried a different version of the exporter? Or better yet, try OBJ instead.

Hi eric, thanks for your response. UV's seem fine from what I can tell - I've attached my unwrap to the original post. ive tried your vertex weld modifier, and the edit normals modifier (did that on both the high and the low. but still giving a similar result. i was exporting as fbx, but this time I tried obj to see if it made any difference, but alas no!

Fabi_G

Hi @michaelarby Throwing the fbx files into Blender, it looks like both low and high poly have parts with inverted normals: 

I flipped those and it bakes as expected in Painter. 

Fabi_G

Additionally, here are some general notes from looking at the meshes:

• Highpoly (for example 'head_high') has some hard edges which will show in the normal map, would shade those soft

• If the edges come out too tight, I would exaggerate the bevels of the highpoly some so they hold up when viewed at a distance. Wiki: Edge Thickness
• Recommend to straighten UV strips and align with pixel grid to minimize aliasing artifacts  Painter Documentation: Aliasing on UV seams

• I think low poly UVs are a bit segmented while meshes are smooth for the most part. I would either add some hard edges where it makes sense (steep angles) and have the UV splits there, or could have more continuous UVs (think cylindrical mapping with some tweaks).

• pin lowpoly has some hard edges without UV splits, that looks unintentional to me.

michaelarby

Fabi_G said:

Hi @michaelarby Throwing the fbx files into Blender, it looks like both low and high poly have parts with inverted normals: 

I flipped those and it bakes as expected in Painter. 

Thank you so much for checking that, and verifying thats the problem. I've not had a chance to open Max again yet, but glad I know what to look for now!

I'm bamboozled though - I checked for flipped normals, unified them, flipped them etc and thought I had eliminated that possibility!

Can I ask - I'm a bit lost with normals as a concept. When I flip faces, is that also flipping the normals? or are they separate? I flipped all the faces on the low poly, and had them facing outwards - in max, you cant select edges on an inward facing face, so I know they SHOULD have been the correct way. 

Also - are there face normals and vertex normals? whats the difference? and do the modifiers we've mentioned work on one or the other? or both?

Thanks again.

michaelarby

Fabi_G said:

Additionally, here are some general notes from looking at the meshes:

• Highpoly (for example 'head_high') has some hard edges which will show in the normal map, would shade those soft

• If the edges come out too tight, I would exaggerate the bevels of the highpoly some so they hold up when viewed at a distance. Wiki: Edge Thickness
• Recommend to straighten UV strips and align with pixel grid to minimize aliasing artifacts  Painter Documentation: Aliasing on UV seams

• I think low poly UVs are a bit segmented while meshes are smooth for the most part. I would either add some hard edges where it makes sense (steep angles) and have the UV splits there, or could have more continuous UVs (think cylindrical mapping with some tweaks).

• pin lowpoly has some hard edges without UV splits, that looks unintentional to me.

Thank you for this! some of these are really helpful

1 - yes, some areas, such as the square bumps in the middle of the head, i left unchamfered purely out of haste. should the high poly have any hard edges at all? is it only the low poly in-game mesh that needs hard/soft setup? are there benefits to hard/softing the high poly?

2 - Will do - thats a great article, though the other sections have left me with even more questions now lol.

3 - THANK YOU!!!! SO MUCH!!!! This issue has been bugging me for years and i never found a proper answer for why it happens. I've seen some hacky fixes for it but this will prevent so many problems for me going forward! Question - those hard lines on the seams in that image as well - are they caused by hard edges that should be soft on the low poly? or are they they just a result of the aliasing artifacts?

4 - Funny - this relates to point 3 - i read somewhere that smoothing the whole low poly mesh will fix those aliasing seams. this may be incorrect. I also heard recently the 'proverb' - 'not all seams are hard edges, but all hard edges are seams'. Am i better to have hard edged areas on my low poly then?

5 - possibly! ive tweaked and retweaked this model so many times im sure i missed something in my haste! ive actually UV packed it twice! for some reason the first (better) unwrap didnt save!

Apologies for all the extra questions but I really appreciate your help!