Issues with textures / models

[sbadkins4]

Hello.
I am a member of a group of modelers/animators trying to add models and animations to HoI4 for several mods.
We have encountered an issue: dark splotches and strange shininess on models that should not be present, and, as far as we can tell, are not in the textures (they appear even if we use plain white textures).
We are using ZBrush and Blender.
Any advice/assistance would be greatly appreciated.
Thank you for your time.

 

[MCN80]

What are your SPECULAR and NORMAL files like?

 

[sbadkins4]

Sir/Ma'am,
For this test we were using "blank" normal and spec maps.
Thank you for your time,
The Captain

 

[ross-g]

I would bet that your mesh has broken/flipped vertex normals ... post your .mesh file and I'll let you know for sure if that's the problem.

 

[Oligarch]

We no longer have the strange shine/chrome effect, but the mesh tears like this in animations, and the models seem to have messed up lighting where the front it is always dark; does anyone have a solution?

 

[Oligarch]

I'm not sure if this is going to work but here is a rar with out mesh in .dae form, maybe this will help.

 

[ross-g]

Collada (.dae) file won't really help, as that's not what goes into game. If you post a .mesh I can actually look and tell you what is wrong with the geometry.

 

[Oligarch]

Can do

 

[Carlberg]

Heya, PDS artist here. I had a look at your mesh in Marmoset toolbag and it at least seemed to be reading the normals correctly. I think this might rather be that you're using a standard blue normal map (127,127,127) but the normal map in HoI4 and subsequent games is retooled a bit with individual channels moved. This is in order to keep the compression artifacts to a minimum as the channels can affect each other. The blue normal maps were used until EU4 but the following workflow below is true for HOI4 and Stellaris.

1. The textures should be .DDS files with DXT5 compression, done with NVIDIA's DDS texture export plugin.
2. The normal map color channels are shifted to the following after you've finished it as a blue normal map:
R - Red channel
G - Red channel
B - Filled with black (this channel controls emissiveness/light)
A - Green channel

As you can see, it's a matter of moving the green to alpha, copying the red one to the green, and just discarding the blue channel (It's redundant in this case and regenerated by the engine). The normal map should now look yellow and black unless it has any emissive data.

3. The specular map has material data in it's channels
R - Nation color (Not in active use, left black)
G - Specular (fill material areas with distinct values, leather should be one value, metal another. We usually block these in and avoid making gradients)
B - Metalness (Anything that isn't metal should be black, metal areas are filled in with a higher value, giving it reflectiveness)
A - Gloss (How 'polished' the area is, black (0) means the surface looks rough, white (255) means the area looks polished, and thus also more reflective)

If you're using the Clausewitz texture exporter and it's using the HOI setup, then it ought to be doing the steps above automatically. But one can also move the channels manually and export it as a DDS manually, just remember DXT5 compression or the alpha data is lost.

Also about those tears in the mesh, is it cohesive and merged? It looks like some edges/vertices might not be fully attached to each other.

 

[sbadkins4]

Sir/Ma'am,
Thank you. Our animator says that all he has done is removed double vertices; could you suggest how else to ensure that the edges and vertices are properly attached? (I apologize for out inexperience.)
Thank you for your time,
The Captain

 

[Oligarch]

Hey there, i'm the animator. in addition to what "The Captain" has said, it also appears as though the tearing is along the UV unwrap edges...
i'm not sure how to solved this...
Thank you

 

[Carlberg]

Not sure how Blender handles it, never used it myself. If I knew I had several vertices that laid on top of eachother, but werent merged, then the Maya merge tool would merge any dots that are really close in vicinity to each other. If a similar tool or function exists in blender.

 

[ross-g]

it also appears as though the tearing is along the UV unwrap edges...

This would suggest that the skinning was not done to specification for Clausewitz, or that it got broken if you are exporting between packages.

The mesh is supposed to split along UV unwrap edges, the exporter will do this automatically and this is completely normal (in fact it's required for basically all graphics rendering). Every time you split an edge/vertex in your UV layout the exporter will actually create another vertex for the game to use. Normally you don't actually see the splits because the vertices just overlap and never move apart. As you can see from the screenshots in this thread, the splits are only visible when the model is animating.

My advice
- removing duplicate vertices is fine, continue to do this
- re-UV your model so you have less islands, the layout is quite poor at the moment
- make sure when you skin your mesh to the skeleton that you have AT MOST 4 bone influences per vertex and that the bone weights are normalised

That last point is the most important one, in Blenders weight painting mode you need to Limit Total and then Normalize All.

 

[Oligarch]

@ross-g
Thank you so much for this reply!
I have a quick question, when you say "That last point is the most important one, in Blenders weight painting mode you need to Limit Total and then Normalize." does this mean that there is a way to automatically set it so a vertex has no more than 4 bone influences or do I need to do that manually?

 

[ross-g]

Yes, both of the steps I mentioned are buttons on the toolbar when in weight painting mode.
https://docs.blender.org/manual/en/.../weight_paint/weight_tools.html#normalize-all
https://docs.blender.org/manual/en/...ng/weight_paint/weight_tools.html#limit-total

I can't guarantee this will fix the problem, but you should be doing these steps anyway.

 

[Oligarch]

@ross-g
Oh my god it worked, thank you so much!
but of course where one problem ends another starts...

2 little things now seem to be in the way. 1st is that you can see white on the texture seems of the UV unwrap in some places, not sure where we went wrong there. and 2nd is if you look underneath the model you can see that weird protrusion(it seems to end where the "root" is, but i didnt name it "root" this time, could that be it?)

 

[ross-g]

You need to extend your texture further so it runs outside of the UV unwrap. (this is called "padding")
https://support.allegorithmic.com/documentation/spdoc/padding-134643719.html

The weird protrusion you have ... I will bet that you have 1 vertex somewhere in your model which is not weighted to any bones. So by default the engine puts this at the root bone (doesn't matter the name of the bone, root is just the top most parent bone).

 

[Oligarch]

@ross-g

THE VERY FINAL STRETCH!!
If you can help us with this very last part, I dont think we will ever have to bother you again
The last issue seems to be this really dark shadow that is completely covering the front of the model.
Any ideas?
We've had this issue for a while and haven't been able to find a solution.

 

[ross-g]

Did you fix your normal map texture as @Carlberg described? Because the one in post #3 above is incorrect.

Simply put, for a flat normal map your texture should be a 4 channel (RGBA) DDS texture with DXT5 compression.
The red, green and alpha channels should be filled with 50% grey colour (127 pixel value).
The blue channel should be filled with black (0 pixel value).

This blank normal map is actually already in the HOI4 files for you to use ... but I have attached it here to make things simpler.
"Hearts of Iron IV\gfx\models\nonormal.dds"

- apparently you can't upload DDS files to the forum, so I have zipped it up.

 

[Oligarch]

@ross-g
Normal mapping should be fine I believe, I think there might be a step in blender with lighting that we are skipping or something.
that being said, ill double check to make sure we did those things you mentioned just in case I am wrong.