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Shadow Matte Alpha Transparency

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Message 1 of 6
Steve_Egrie
462 Views, 5 Replies

Shadow Matte Alpha Transparency

Hello,

I'm using the Shadow/Matte material inside of 3DS Max and trying to get get the alpha of the image to display the shadow as a transparency. Image 1 is the building that I'm rendering out. Image 2 is currently how the alpha gets rendered out with the shadow being fully opaque. Image 3 is what I want to achieve with the shadow.

8404-shadow-alpha.png

This is the material settings I have for the ground plane.

8405-screenshot-7.png

Any help would be appreciated.

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5 REPLIES 5
Message 2 of 6
madsd
in reply to: Steve_Egrie

Control the contribution to the alpha on the matte closure not the shader.


8393-qwe.png

Message 3 of 6
Steve_Egrie
in reply to: madsd

That works. Thank you so much!

Message 4 of 6
smegrie
in reply to: madsd

We've run into some issues with using this approach. Some of our objects extend below the ground plane. Since it's being set using transparency the part of the object below the ground should not be viewable but is showing up. I've attached an image. 1 is the render with the object extending below ground. 2 is the bottom part of the object below ground that shouldn't be showing up. 3 is a viewport view inside of Max with a low angle. 4 is how the alpha should look. Is there something I'm doing incorrectly or is there another solution? alphaproblem.png

Message 5 of 6
madsd
in reply to: smegrie

https://docs.arnoldrenderer.com/display/A5AF3DSUG/Clip+Geo

Use the clip geo closure, it will automatically cap off anything inside it.

Here the box is cut dispite it is nested into the ground and the alpha shows a clean result. Note you need to add an Arnold properties modifier on the clip box and disable shadows so they dont translate to your alpha.

qweqwe.png

Message 6 of 6
smegrie
in reply to: madsd

Yup, that did the trick! Thanks so much.

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