[Solved] [3ds Max/Arnold] Mikkt Normal Map problems/conversion.

Dihemi

Hello anyone.

I had some weird black border artefacts whenever I render low-poly objects with Arnold (3ds Max). The artefacts do not appear in Sketchfab, Substance Painter or Unreal. After some troubleshooting and looking on the internet, the issue seems to be that the normal maps are in "Mikkt" space (baked in Substance painter) as opposed to Tangent space non-Mikkt. 3Ds Max's Arnold (and Maya, from what I read) does not support this Mikkt normal map format, resulting in black outlines on sharp geometry vs camera angles.

Most information I could find on the internet about Mikkt normal maps in relation to 3ds Max was rather sparse, so I was wondering if anyone could answer these questions;

- Is there a way to make Arnold (3ds Max) Mikkt compatible? Most info says no, but the information I could find was somewhat old.

- Is there a way to make Substance Painter not bake normal maps in Mikkt format? Or even convert them on export (I'm looking into export configurations at the moment, but have little experience/hope that this might fix anything).

- Is there any other software that gives you the choice to bake in either Mikkt or Tangent space non-Mikkt? Or, ideally, convert Mikkt normal maps to tangent space non-Mikkt normal maps?

Again, I have little experience with this "Mikkt" format (don't even know what it stands for) and only know it's "better" or something for real-time renderings. Any additional information could be helpful.

Thanks in advance.

Edit: Mikkt is a Tangent space type as clarified by rollin.

Edit: Upcoming 3ds Max (2021) will support Mikkt.

rollin

Sorry, can't help you with Arnold but just to clarify:
""Mikkt" space (baked in Substance painter) as opposed to Tangent space" 
The point is MikkT IS tangent space.. but there are multiple ways of calculating tangent space and MikkT turned into some kind of standard


Edit: I just realized this is the perfect explanation why there are so many different tangent spaces possible and how one feels when dealing with them

oglu

The normalmap alone is only one half of the puzzle. You need the geometry in the same tanget space as the normalmap.

In this Max webinar on Wednesday there might be some great infos. 
https://autodesk.zoom.us/webinar/register/WN_EniSHfdWQd2rWYLsTfzt5g?fbclid=IwAR1RbAoeMFxNGF7RUGOHGajsnYFzgeo-hhiz41aOTjC7pH_Fxbs

Noren

You can also try object space if your meshes aren't deformable and you don't mind that they aren't as compressible. And Handplane was pretty good at converting object space normal maps into different tangent space formats last time I checked (which was a couple of years back, though.)

Dihemi

rollin said:

Edit: I just realized this is the perfect explanation why there are so many different tangent spaces possible and how one feels when dealing with them

Yeah, one of my annoyances with this problem is that, until recently, I didn't even know I was baking "Mikkt" and the artefacts weren't even on my part. I just assumed I messed with some settings.

oglu said:

The normalmap alone is only one half of the puzzle. You need the geometry in the same tanget space as the normalmap.

In this Max webinar on Wednesday there might be some great infos. 
https://autodesk.zoom.us/webinar/register/WN_EniSHfdWQd2rWYLsTfzt5g?fbclid=IwAR1RbAoeMFxNGF7RUGOHGajsnYFzgeo-hhiz41aOTjC7pH_Fxbs

Geometry and normal map are the same. Looks good in Sketchfab/Unreal/Substance but the same assets give artefacts in 3ds Max/Arnold. So geometry shouldn't be the issue. I won't have time to attend that seminar, but from what I gather Mikkt support has been a requested feature for 3ds Max/Maya for some years. So I'll try to keep an eye out for any updates post Wednesday/seminar.

Noren said:

You can also try object space if your meshes aren't deformable and you don't mind that they aren't as compressible. And Handplane was pretty good at converting object space normal maps into different tangent space formats last time I checked (which was a couple of years back, though.)

Ok, doing a quick look it (HandPlane3D) does distinguishes between different tangent spaces for different software. So I might take a closer look into this tool. But the interesting thing is, so does Substance painter; the export configuration does seem to support Arnold materials (even distinguishing between different shaders). From what I gather this Mikkt format is created on baking level, not export. So don't know what's up with all that. 

Thanks for all the replies. Holy grail would be something that allows me to support/fix Mikkt into itself 3ds Max.

oglu

Hmm im not sure if that should be there. But it looks like MAX 2021.
http://help.autodesk.com/view/3DSMAX/2021/ENU/?guid=GUID-566A8DA5-C3EA-472F-B846-AB334616D6BD

Dihemi

oglu said:

Hmm im not sure if that should be there. But it looks like MAX 2021.
http://help.autodesk.com/view/3DSMAX/2021/ENU/?guid=GUID-566A8DA5-C3EA-472F-B846-AB334616D6BD

It does.

So coming the next 3ds Max update (2021), this shouldn't be an issue any more. Substance painter's normal maps should be compatible with 3ds Max. Just a bit silly I happen to post this a few days before it also gets fixed. Problem sort of solved.

rollin

The only thing silly is that it took them that long... 

Dihemi

rollin said:

The only thing silly is that it took them that long... 

This whole ordeal had at least some silver lining. Now I know that not all Tangent Space normal maps are equal or the same. Until a few days I just assumed all normal maps adhered to a standardized convention.