Thank you for trying my asset! I would suggest taking a look at the "Draw GUI" events for the CRT object, where you'll see that the rendering is wrapped up in a single function call. If you call this function while your surface is the current target, the CRT screen will be drawn directly to your surface instead of the GUI surface. You'll need to ensure that crt.output_width and crt.output_height match the size of your surface, and I'd also recommend disabling the phosphor mask if your surface will be zooming or stretching around the screen.