Rendering transparency problem

# 1 13-11-2013 , 09:53 PM

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Join Date: Nov 2013

Posts: 3

I'm working on a scene at the moment with a 3d model lit by a basic 3-point light setup. I need to have labels coming off of the model with information. To do this I created a poly plane and applied a default lambert. In the colour node I applied the label image, which is basically just text on a transparent background. However, when I render it out in mental ray the plane is slightly visible. I assume this is due to the fact that the plane is receiving light information. Is there a way that I can stop this from happening? I was thinking that one option would be to stop the plane from receiving any light information and have it self-illuminate, but I don't know how to go about this.

Unfortunately I can't post images as it is for a client, but if any more information is needed then I can try to provide it. Any help would be really appreciated.

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# 2 13-11-2013 , 10:10 PM

EduSciVis-er
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Location: Toronto

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Have you tried plugging the label texture into the transparency attribute? That might provide the cutout you need. You may have to reverse the black/white in the label image.

-stwert

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# 3 13-11-2013 , 11:02 PM

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Location: Bolton - UK

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I have come across this before and its because a setting with transpancy is defaulted at 0.8 not 1.0.

But cant for the life of me remember which one it is off the top of my head - go thought the shadders options and see if you can find it - i check once im next to my pc.

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# 4 13-11-2013 , 11:35 PM

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Thanks for the help. Annoyingly I'm still having the issue. I forgot to mention that one of my lights is using light fog, which seems to be the source of the problem.

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# 5 14-11-2013 , 01:08 PM

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Right looking at my old file I see some of the things I did to correct the problem.

1) (And I do this for every texture now) under the file attributes > Filter type > set to off
2) A default lambert's diffuse value is always set to 0.8 > change this to 1.0
3) Under render settings > Quality> Shadows > Shadow methord > set to sorted or segments not simple.

These settings sorted out my problem I hope they help with yours

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# 6 18-11-2013 , 12:55 PM

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Thanks very much for the help. I decided in the end to just model the labels in Maya with text and polygon shapes, but I'm sure your response will be useful at some point in the future.

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# 7 18-11-2013 , 09:33 PM

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It's the "Shadow Attenuation" attribute on the shader, it's in the raytrace options section Set it to 0.000, by default it's 0.500 which causes the slight shadow even on 100% transparent surfaces.

- Genny
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Rendering transparency problem

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