It’s a strange bug.
I’ve tested the script under 3ds Max 9 x64 but there’s no slowdown on my computer.
In fact, I check if the viewport window size was changed whenever a stroke is painted. If so I update the Graphics context.
Maybe there’s something wrong with the .NET framework code I’m using while running on your computer. The timer or the drawing methods.
I have an utility plugin doing the same things but not using .NET. It uses C++ GDI+ and a Win32 timer. It’s faster than the script but less fun.
But I think the best approach is to develop something like thePainterInterface which would give MAXScript access to start/end painting strokes and setting parameters. I’ll try to develop such tool if I have the time.
That’s a nice tool, Yannick!