View Full Version : rendering volumetric lights

11 November 2003, 11:32 AM
How do you render out a volumetric point light on a transparent background?

I do know how to set the backgournd transparent, and how to create my volum. point light, but when I render out, all shadows are present, but my light itself is gone.

example below


11 November 2003, 02:20 PM
Why not render the background in black and use the "screen" mode in Photoshop to get rid of the black? Other than that, I'm not sure...I'm not expert at rendering.

11 November 2003, 02:28 PM
The problem is, i realy need it transparent, because the ultimate goal is to import it in flash.
When I render out on black, everything behind the light won't be shown. :hmm:

11 November 2003, 02:31 PM
save it as a 32bit .png file. Flash works well with png files...with transparency

11 November 2003, 02:40 PM
I agree, however,
The light doesn't apear directly in flash neither.

It's the same effect as above.

11 November 2003, 02:43 PM
I think, Flash might be the problem. I haven't had any problems with Lightwave's alpha channel so far, but didn't import anything into Flash, yet.
Have you imported the image into other applications (e.g. After Effects), yet?

EDIT: Something that comes to my mind - you could do that glowing point light very easily in Flash itself...

11 November 2003, 02:48 PM
I've tried several apps, it doesn't show in either one.

I know you could simulate the point light, but you cant simulate the shadows, as the image show is just a sample.
Objects pass, so the shoud receive a bleu glow.

11 November 2003, 02:51 PM
My though was more a workaround... I'd also be interested in a solution for your problem - who knows when I'll face something like that somewhen.... :hmm:

Have you already tried other image formats and rendered the sequence via render options? Maybe LW's image viewer causes the problem :shrug:

11 November 2003, 02:56 PM
It isn't the viewer.
I've rendered full sequences and tried to save as all possible 32 & 24 bit images.
I even made a QT & avi to import.

the pointlight is nowhere to be found.

11 November 2003, 03:09 PM
maybe this thread helps:

11 November 2003, 03:41 PM
Thanx Tommi, :beer:

It works, however, now all furfaces with shadow density are ignored.
But with some tweaking, I think i could isolate the part I need.

11 November 2003, 04:29 AM
Don't you need to use Ray Trace Transparency (in your render settings) to see volumetric effects behind/inside transparent surfaces?

11 November 2003, 08:23 AM

even with ray-trace transparancy on the light doesn't show.
Pitty, could have been a great solution

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