Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Alphabetic on 2019-01-17, 22:03:22

Title: Transparent background in video with an HDRI
Post by: Alphabetic on 2019-01-17, 22:03:22

Is there a way to use an hdri to light geometry and render a video with a transparent background?

Title: Re: Transparent background in video with an HDRI
Post by: Frood on 2019-01-18, 08:55:54

The background is already "transparent" as it does not affect the alpha channel. If you mean compressing a video with alpha channel/transparency you have to choose special codecs to do so (for compositing). Maybe you could show some images to clarify what you mean exactly?


Good Luck

Title: Re: Transparent background in video with an HDRI
Post by: Alphabetic on 2019-01-19, 03:12:09

I figured it out. I just rendered a .mov and set the compression type to PNG. Other types were giving me a black background when I imported frames to photoshop.

Title: Re: Transparent background in video with an HDRI
Post by: TomG on 2019-01-19, 21:52:56

BTW, rendering straight to a video format is never a good idea, best to render to PNG and then composite to video afterward. The two biggies are:

- If the machine crashes, the power goes out, etc., ALL of your render is lost when rendering to a video format and you have to render everything again from the beginning. With stills like PNG you can just pick up and continue where you left off
- Video compression is baked in at render time if rendering to a video format. If it turns out to be inadequate, you have to redo the render from the start. With rendering to stills, you can just redo the video encoding part of the process

Just as an fyi :)

Title: Re: Transparent background in video with an HDRI
Post by: Alphabetic on 2019-01-19, 22:05:35

I don't know whyI've never thought of that. Thanks for the tip, Tom!

Title: Re: Transparent background in video with an HDRI
Post by: TomG on 2019-01-20, 20:13:41

Most welcome! I learned that the hard way of course ;)