Hi there, I'm looking to automate the -3DClip command in AutoCAD. Basically, I want to set my view according to a specified elevation and thickness. For example, in a 3D drawing with 1m surface contour lines, I want to only look at contours at the 750m elevation. I would enact a program to set the viewport to clip everything above the 751 elevation and below the 749 elevation. Right now, I have to manually play with the front and back clipping and in a big drawing this can be a real pain. I am fairly well versed in AutoCAD VBA, but I've never really delved into viewport commands. Any ideas? Much appreciated.