ST mapping does not work for me


Hi, I am trying to make ST mapping work.

I put a multipass EXR-file to a STmap-node, defined a source image and set U and V to their according channels. What am I doing wrong?

Here are my diffuse and UV passes:

postcard_test.exr (1.2 MB)

Here is a screenshot:


Just make sure the incoming Alpha is correct. For testing purposes you can set it to white (1):



Thank you Josef, it works, which is great! But how can I prevent the dark borders around my postcards?

I played around with some (un)premultiply settings and switched the shuffleUV`s alpha to one of my channels called “Front.R”, but it still remains .


How does your alpha look like? The artefacts shouldn’t appear in case your alpha is correct.


The alpha channels (red and green) are included in the file above and they are razor sharp:

I was able to reduce the unwanted borders slightly by disabling “black outside” on the STmap-node. Nevertheless, its still very much visible:


After shifting the UV offset values in the STmap-node a bit I think it has more to do with my ST map overlapping than with the alpha map. There are some transition zones that on the edges that mix up the ST-coordinates.


I should probably separate my ST-map in front and back sides (and maybe even apply some bleeding which gets cut away by alpha later?).