Symmetry and Normal Maps?

FULGORE

First off, fantastic package. Easily my favourite way to present stuff. However, I honestly don't know if I'm making some rookie mistake, or something like that, but I remember not having this issue in Unreal, I think? (instead, iirc, the only issue Unreal had with normals and symmetry was a seam here or there)

Had the same thing going on with a mig welder, where for the half of the casing I made symmetrical, the indents appeared to be poking outwards and vice versa

e.g.


^ This was a little test involving the simplest of all baked normal maps on 1) a plane with a copy of itself mirrored and attached, and 2) a plane with symmetry. These weren't baked with the other half already there and UVs shifted 1 grid away, but I did that with the mig welder to no avail (just stuck to taking shots from one side of the asset)

Am I making a simple mistake here?

EarthQuake

You shouldn't get errors like this, unless there is something funky with the normals of the mesh itself. For instance, I've seen a lot of people mirror things in maya by giving them a negative scale, which can mess up the mesh normals.

Some more info would help.

What are you modeling in?
What format (and what settings) are you exporting out?

Also if you could upload your mesh and texture I can take a look at it as well.

FULGORE

I'm using Max, exporting to FBX, tangents & binormals checked. Happens to triangulated meshes as well as the above, which are just planes smushed together.

If you'd like to see what's going wrong, that'd be awesome Here are the couple of test meshes and the freshly baked normal map (I take it linking to public dropbox files works?)
https://dl.dropboxusercontent.com/u/41252375/test_method_1.FBX
https://dl.dropboxusercontent.com/u/41252375/test_method_2.FBX
https://dl.dropboxusercontent.com/u/41252375/test_NormalsMap.tga

EarthQuake

Yeah that works, thanks, I'll take a look at these soon. Shot in the dark by try exporting as OBJ as well, I know people have had issues with FBX exporting in certain versions of Max.

EarthQuake

Actually, it looks like max is exporting some funky tangents. This is a really quick fix, you shouldn't even need to re-export anything. Go to the properties for your mesh and select Max from the tangent space drop down. This should fix it.

You may see similar problems if you try to load the same mesh into Unreal 4 with the import tangents from mesh option as well.

FULGORE

EarthQuake wrote: »

AGo to the properties for your mesh and select Max from the tangent space drop down. This should fix it.

Spot on! Tiny simple thing I didn't think to check. Thanks a ton no more seams/wasteful UVs

EarthQuake

Awesome, glad that fixed it.

Quack!

I just want to add to this that 3Dsmax 2014 exports FBX files incorrectly. This exact problem will happen because of it. So use anything but 2014 to export FBX to also fix it.

EarthQuake

Yeah or just use OBJ, as OBJ doesn't support tangents.

almighty_gir

Quack! wrote: »

I just want to add to this that 3Dsmax 2014 exports FBX files incorrectly. This exact problem will happen because of it. So use anything but 2014 to export FBX to also fix it.

Is this also true if you choose an older version of FBX to export from max?

Talking about this here:

Quack!

If you use 3Dsmax 2014 to export that dropdown is irrelevant, you still get broken meshes from FBX. I tried FBX2013 and FBX2012 from Max2014 and both gave that same problem. It seems 3Dsmax2014 is what is broken rather than the fbx plugin.

I had to export from 3dsmax 2015, 2013 or 2012 to get it to work. This problem was carried over to UE4 and Substance designer.

almighty_gir

Interesting, thanks for the info Quack!