She was wondering if an image could be rendered in Bryce so that when it’s taken into PhotoShop less work would be required removing the background and cleaning up the edges. A mask sound like it might work for what she wants, but I’ve never done this so I’m not sure of all the what/when/how/etc. of making one. I also question how it should be saved so it can be used by others using other graphic programs.
What you’d have to do is do a regular render of the object, then select just the object and choose ‘Object Mask’ in the render options and render again. This time you’ll see a black and white render with the background black and the object white.
Save the Object Mask render in which ever file format you prefer really (I use .tif) and save it with the real render.
Then open the real render up in Photoshop and you have several choices;
Using the ‘Channels’ tab, create a new channel and then import the Object Mask render into it. This will then enable you to save the picture in a format that supports alpha channels or alternatively in the top menu under ‘Select’ there is an option to ‘Load Selection’. Set the ‘Source’ to alpha channel it will put a selection around the object for you (because it uses the Object mask render to know where the edges of the object are). You can then reverse the selection and hit delete to erase the background in the real render, or turn the selection into a path (in the ‘Paths’ tab. Then save the Path and make it a ‘Clipping Path’. This enables the picture to be saved in several formats for use in other graphic and page makeup applications (In Design, Quark Express etc.) with a transparent background.
Alternatively, you can create a layer mask and import the Object Mask render into that, this will make the background transparent without having to actually delete it. Then you can place a different background picture on another layer beneath it.
Cleaning up edges is unnecessary, if it’s a bit pixelated, you can feather the edges of the object mask.
If you choose creating an Alpha Channel in Photoshop, you can then save the picture out as a .gif along with it’s alpha channel and when displayed on the internet, it will have a transparent background like you described when the other person posted it.