CompuServe Messages

Dear Blackbelt, I have a question regarding your Win:f\x package. I'm trying to automatically composite hexagonal light "glows" or halos (Asterize) into a rendered animation. The animation, rendered in 3D Studio (PC rendering software) shows a night street scene with several streetlights on either side. The camera moves down the street, between the lights. The effect I'd like to achieve is to have the hex glows show where the street light bulbs are and have them "grow" accordingly in perspective as the camera moves down the street. I rendered one pass with all objects in the scene. Then I hid all objects and rendered another pass in which bigger, self-illuminated spheres of different colors were substituted for the streetlight bulbs. In other words the second pass shows the stand-in spheres as circles of unique, solid colors on the black background, moving and growing in perspective towards the viewer. These circles should determine the size and position of the desired hex glows for individual street lights. In Win:f\x, by color-sampling each of these circles (or stand-in spheres) and choosing the Magic Wand area selection I am able to determine the exact area to be filled with the Asterize hex glow for each street light. Here's my problem: how can I use the area selection in one image (Magic Wand & the stand-in spheres) to put the hex glows on top of another image (fully rendered street scene)? I know how to set up the area selection lists (for each color), image lists, operation settings lists, etc for animation processing. But I can't figure out how to use the area information from the second pass to composite the hex glows on the corresponding frames in the first pass. I tried setting up the spheres as the source image and the street scene as the target to Make Alpha, but I couldn't get it to work correctly. Could you please enlighten me how to proceed? Thanks for any hints, Greg