So I'm writing this just as a helpful tip (hopefully it's right...our resident Nuke guru okayed this so I'm gonna go ahead, but if you have more to say on the subject feel free to critique!) and I'm not really posting a question. I'm also writing it here so if I Google this problem I stop getting no good answers since I'm probably going to forget this...
So basically, if you don't have Photoshop installed, or are just plain sick of using shitty non-node based workflows and you use Mudbox but none of your godamn layers match up keep reading, ALSO NOTE: this fails if you have different layer blending modes on in Mudbox...this stuff computes differently than Photoshop so I haven't tested and usually never set blending modes anyway when painting since they're kind of shit most of the time:
In Nuke:1. Place all of your nodes in the right order as compared to your Mudbox paint layers and setup Merge nodes between them set to the default Over setting.
2. Set the Mix value to the same as the opacity value on the paint layers as well.
Now we've got the nodes all setup but it still shouldn't look the exact same as if you merge and export the layers in Mudbox! So here's what you do:
Project Settings -> LUT Settings -> Set all of them to Linear
Read Nodes for your textures -> Turn them all to Linear
Now you should be getting the proper look of the EXACT same as your layers in Mudbox. The reason for this is:
|Mudbox does everything in sRGB colorspace and as a result the textures output like that (correct me if I'm wrong on this one). As a result all of the actions ALSO happen in sRGB colorspace such as opacity and alpha maps that get spit out with those textures. Nuke does everything in Linear colorspace so all of the merge nodes combine the layers using alphas that SHOULD be based on linear colorspace, not sRGB. So none of these layers have the correct opacity or alpha maps in linear space so we need to set Nuke to interpret all data with no correction on to compute everything properly.|
If that doesn't make sense...well...hopefully this thread builds so I can personally understand this process better anyways. Well I hope someone took something good away from this and can now put their layers back together properly in Nuke! I know it's been a vexing thing for me at least...