Quicktime alpha channel not processing properly when on different Z level

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robertwinter
Posts: 46
Joined: 27 Nov 2012, 21:53

Quicktime alpha channel not processing properly when on different Z level

Post by robertwinter » 26 Sep 2018, 02:27

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
Attachments
Alpha issue.jpg
Last edited by robertwinter on 26 Sep 2018, 02:30, edited 3 times in total.

robertwinter
Posts: 46
Joined: 27 Nov 2012, 21:53

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

Post by robertwinter » 26 Sep 2018, 02:28

Scene.png
Scene.png (13.19 KiB) Viewed 163 times


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lerou
Posts: 294
Joined: 06 Sep 2013, 07:14
Location: Hamburg, Germany

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

Post by lerou » 26 Sep 2018, 11:20

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.

robertwinter
Posts: 46
Joined: 27 Nov 2012, 21:53

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

Post by robertwinter » 26 Sep 2018, 22:07

I knew it had something to do with the draw order and was unfamiliar with the ZSort node. Implementing that fixed it.

Thanks Rou!

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