Alpha and transparency issue

[Macer]

I'm working on an animated bubble (picture a large soap bubble) and have to be able to overlay it onto a web page afterwards (don't ask!).

 

I've resorted to using hdri environment to get nice reflections and a realistic looking bubble, but the hdri appears in the background too. My alpha channel is showing completely white for behind the bubble (black outside it though) meaning that when I go to overlay it, I get no transparency for the bubble - the background is still there (but it does cut out around the outside of it), you can see the hdri environment through the bubble - which I don't want, as well as in the reflections, which I do want.

 

I'm sure that there is an easy way to render without the hdri showing up but my brain stopped working and I can't figure it out - Its not like I've spent a lot of time making bubbles before!

 

I can't use the reflection slot because that contains the maps that give me the rainbow like swirl of colours....

 

Like I said, I'm sure it simple, but help please?

[Crazy Homeless Guy]

For the background, try the "Environment/Background Swither (mi)" shader. It will allow you to separate the environment reflections from the background image.

 

As for the alpha... Not 100% sure, but if using a A&D shader, double check that the "Transparency propagates Alpha channel" is ticked. It is under the Advanced Rendering Options in the A&D shader roll out. If that doesn't do it, maybe try the process background and environment under the exposure roll out.

[Macer]

Great, thanks for the reply. I'll have a play with your suggestions tomorrow.

 

Cheers.

[Macer]

Thanks Crazy. Your tips were bang on! Just what I needed, they worked a treat.