I'm afraid you're going to need to be more specific. What numbers? What specifically about the render engine? Are you talking about output file size? If so, that is set up under the "File/Document Settings..." menu item. The numbers there are the viewing area size in pixels, i.e. 800x600 pixels. You can then render the final output at 4:1, 2:1, 1:1, 0.25:1, etc. meaning 4 times larger, or 25% the size, etc. This would translate to 3200x2400, 1600x1200, 800x600, and 200x150 pixels, respectively. Pixels are just pixels: on screen, there are typically between 72 and 90 pixels per inch, depending on your monitor. If you're eventuallly going to print your Bryce images, it depends on your printer -- an ink jet printer (for example) will produce its best quality output if you print at about 150 pixels per inch... NOT the 1440 resolution that some printers claim, which is for 4-color printing, not continuous-tone printing. So if you want your image to be 5 inches wide, printed on an inkjet printer, it should be about 650 pixels in the horizontal dimension. I apologize if this doesn't answer your question: if not, please be more specific and we'll be happy to help. --flick