I'm trying to place a height map/terrain image (it's an obscure shape with transparency) in CityEngine but whenever I add it I end up with strange height extrusions around the border of the image. I've tried to export the image as cleanly as possible without anti-aliasing/compression, etc. and I've saved it as a PNG-32 with transparency, but whatever I do ends up with the following result:
Is there any way to tell CityEngine to ignore or clip out the messy border on my terrain? Or is there another way to prep the file so that this issue doesn't occur?