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Quicktime alpha channel not processing properly when on different Z level

Posted: 26 Sep 2018, 02:27
by robertwinter
Using v.5.4.1, I put three different colored rectangles on the screen that are next to each other. I want to highlight the center rectangle by scaling it up slightly and changing the Z level to be in front of the other two rectangles. So far so good.

But if I add a Quicktime with alpha behind the center rectangle (at the same Z level as the center rectangle), any subsequently rendered rectangles disappear behind the Quicktime.

You can see what is happening below. The red and blue rectangles are at Z level 0, the Quicktime and green rectangle are at Z level -1.

I've added a Scene archive here as an example - https://we.tl/t-HbV2Uf19bt

Re: Quicktime alpha channel not processing properly when on different Z level

Posted: 26 Sep 2018, 02:28
by robertwinter
Scene.png
Scene.png (13.19 KiB) Viewed 561 times

Re: Quicktime alpha channel not processing properly when on different Z level

Posted: 26 Sep 2018, 02:29
by robertwinter
Alpha max.jpg

Re: Quicktime alpha channel not processing properly when on different Z level

Posted: 26 Sep 2018, 11:20
by lerou
the alpha is handled correctly. Your problem is the draw order. You can't draw a close object with alpha and then a far object behind the first one. You need to draw the far object first. Try changing the draw order and it will work. If you need more dynamic, use the ZSort node.

Re: Quicktime alpha channel not processing properly when on different Z level

Posted: 26 Sep 2018, 22:07
by robertwinter
I knew it had something to do with the draw order and was unfamiliar with the ZSort node. Implementing that fixed it.

Thanks Rou!