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Problem with matte object and alpha contribution set to -1

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  • Problem with matte object and alpha contribution set to -1

    Probably a really simple solution but still one that I am missing.

    See attached image. That's showing the alpha channel of a render of a handle on a shelfdoor.

    What I want do do is very straight forward. Set door do matte, alpha -1, shadows and affect alpha checked in Direct light property box. What I expect from this is a render where the handle is rendered in the alpha channel and the door is not. I want the shadows to be visible as a gradient in the alpha channel. But NOOO - ain't gonna happen. Why?

    This is an scene I have taken over from an old project and it's not me who created the scene. If I set up a new scene with some dummy objects it all works out just fine.

    I have tried to merge the scene to a new file but as soon as I have merged anything from the "corrupt" scene the problem appears. It also doesn't matter on what objects I do this. Even if I create two new objects and render I get the same problem as in attached image.

    Anyone ever experienced anything like this before?

    It doesn't matter if I change the settings in the vray object properties or if I add a material wrapper material - same result.

    I have also tried to save the scene to an older maxversion (max2015, max2014 etc) with no luck.

    If I set the door to alpha -1 but doesn't check the matte checkbox it works out alright - but then I don't get the gradient in the alpha channel that I want - and need.

    Getting frustrated here.

    Cheers!

    Click image for larger version

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    Logic - the art of being wrong with confidence

  • #2
    Anyone? I'm going bananas here...
    Logic - the art of being wrong with confidence

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    • #3
      FYI:
      Hmm - it seems as if it's something to do with the dome light(with a VrayHDRI assigned). If I uncheck the "cast shadows" checkbox in the dome lights options dialog it works as I want it to.
      Logic - the art of being wrong with confidence

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      • #4
        also chek if in your wrapper mat has a vray mat as a base mat ...newer Vray cant have standard anymore as base mat

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        • #5
          Thanks tambyra. I never use other than vraymaterials but since this is a scene I have not created myself you never know what weird stuff one might find...
          Logic - the art of being wrong with confidence

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          • #6
            No prob, did it work?

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            • #7
              Unfortunately no. It gets better than before but still not as it's supposed to be. It wasn't the materials either - there are only vraymaterials in the scene. I don't use the materialwrapper but when I switch to that just to try I get the same result...
              Logic - the art of being wrong with confidence

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              • #8
                On your material under reflection -> affect channels do you have it on anything other then color only? If not reflections will affect your alpha. If that's even the issue.

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                • #9
                  Could you attach the scene or send it to support ?
                  Zdravko Keremidchiev | chaos.com
                  Chaos Support Representative | contact us

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                  • #10
                    Thanks for the tip frothlord but unfortunately that doesn't help. I have tried with all variations selected in the reflection rollout just to eliminate that as an issue.
                    Logic - the art of being wrong with confidence

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                    • #11
                      Thank you Zdravko - I will do that.
                      I will not be att the office for a couple of days but when I get back I will upload a scene either here or to the support.
                      Logic - the art of being wrong with confidence

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