Author Topic: *** SOLVED *** Motion Blur and Alpha Channel  (Read 2183 times)

2020-07-08, 00:47:50

BigAl3D

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I hope all is well in the Corona Renderer world. I'm not sure if this is a still-broken feature or a feature that hasn't been added yet, as I have had this problem before. I have an object that is moving, and I have a slight motion blur turned on. When I bring the PNG files into AE, there is a noticeable white halo around my object. I can't fix it. If use a matte choker, I lose a lot of detail in transparent areas. I've tried rendering as separate passes, but with the same results. In this case, I could render without motion blur, but of course, it looks better with it.

Is there a solution that I missed?

Thanks.
« Last Edit: 2020-07-10, 05:03:42 by BigAl3D »

2020-07-08, 13:47:49
Reply #1

burnin

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It depends on how you tackle alpha in your compositing/editing software.
Quick test with Blender shows it's fine.


2020-07-08, 19:05:27
Reply #2

BigAl3D

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I appreciate you looking at this. I'm rendering out a file with alpha to post. I have to run out, but will post it when I get back. Also, how did you "tackle" the alpha in your example? I do this all the time, but when there's motion blur and an alpha, I get this issue. Thanks.

Just updated this post with the same frame, but not motion blur.
« Last Edit: 2020-07-08, 19:48:47 by BigAl3D »

2020-07-08, 23:17:31
Reply #3

burnin

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Aha, uncheck Straight Alpha in C4D under Render Settings/ Save. It makes semi transparent (gray pixels) solid alpha.

2020-07-09, 02:43:13
Reply #4

BigAl3D

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Ah success! We were both wrong. After many render tests, the answer is a Corona Compositing Tag on the Corona Sky object set to NOT Seen by Camera. I also have a Corona Sun object, but this did not affect the outcome. Keep in mind, I now am able to use motion blur. Thanks for the help.

P.S. I only rendered this final test with 6 passes, so it's a little grainy.

2020-07-09, 11:00:29
Reply #5

burnin

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Oh, I didn't use compositing tag in my case. But I guess same thing happens, straight alpha gets used because of compositing (preventing color issues ;)

Glad you solved yours.
« Last Edit: 2020-07-09, 11:04:09 by burnin »