You can instruct Apo to export a upr of a flame with any number for Sample Density - I use 400 as a good compromise that doesn't take my rig (P4 2.53gHz) too long. It's in the "Options"-"UPR" tab in Apo. Also, if you scroll down in the Outside tab once in UF, you'll see a box called "Background Color". Open that box and you'll find a slider at the bottom of the window that controls the opacity of the background. Pull it all the way left to zero and you'll have a flame in UF with a transparent background. Rick