I am trying to render a simple transparent background ( no background ) behind a single model - like is possible in Poser - .png file. It renders out transparent. How do I do this in Carrara?

1. select a file format that can have alpha channels (Tiff, PSD).
2. click on Render Alpha Channel

If you have a background or backdrop it will render, but will only show if your viewing program can't  use the transparency.

Thank you hdaggers. I didn't know it was that easy!

I'm obsessed with the flaming sword!

Just one more - couldn't make it a transparent background - the flames were edited in PHotoshop for this one, and I couldn't figure out how to add to the alpha channel as I pushed/ smudged the flames around - does anyone know how to set that up in Photoshop? I smudged the flames around, and then realized the alpha channel was set - it needed to be adjusted and what I added on maybe a new layer, that needed to be added to the alpha channel. I don't know.

Hope I can explain this clearly.
In Photoshop duplicate the image .Select the background with the magic wand and  click delete.
Close the "eye" on the original background image.
Save the result as a .png file.

Hope that helps.

Is this helpful?

You're the man Brian, thank you. I've been trying to learn how to do this for a long time. I had to paint the alpha mask around some of the flame, and this is a bit messy, but the process is working. If I take more time, it will look better. If I can learn to just select colors, then I wouldn't have to rely so heavily on the wand tool, but this is working. Thanks again.

It can be very helpfull at times to change the value of the wand. I think 32 is the default setting.
Keep that in mind. You can start off with a low setting and gradually add areas with the add to selection un til you get exactly only what areas  you want.

A brilliant tool!

If you render ot a Targa with a black background it will give you a transparent background.
cheerio  lululee