Alpha problem with backplate

Corona Corona for Cinema 4D General
1

Hello,

I’m on Mac with Corona 6 hot fix 1 and C4D s22.

I have a simple scene with a backplate for the sky (not for lightning the scene but only for visibility). This backplate is assigned with a light material where I put the picture of the sky. This material emits no light (Emit light to OFF) and in the advanced settings I have unchecked the Visible to alpha channel…

Now when I render the images, the backplate is still visible in my alpha !!! why is that ?

Thanks for your help.

Best

stefan

2

Hi Stefan,

Can you share your scene with us via our private uploader?

3

Hi,
I have just uploaded the files

4

Hi Malindis,

Is this what you were trying to do?

Alpha_house.jpg
Alpha_house.jpg1280×720 21.7 KB

Alpha_house.jpg
Alpha_house.jpg1280×720 21.7 KB

5

yes, what am I doing wrong :confused:

6

For your clay material, I enabled “Always black” in the alpha mode.

Alpha_house2.jpg
Alpha_house2.jpg668×753 52.9 KB

Alpha_house2.jpg
Alpha_house2.jpg668×753 52.9 KB

7

OK but what do I do when I have multiple material assigned to my scene :confused:

8

It should be working by default so it looks like there might be a bug with a light material on a plane when working with the alpha channel. Instead of the background plane, you could replace that with a Corona sky and set the projection to frontal. With a few tweaks, you should get an identical look as to that of the background plane.