Having played with impression some more, I am finding it often falls over when trying to zoom. Makes you wonder if it has something to do with the graphics card. Sketchup (which Impression seems to be trying to emulate in some respects) has the same problem, though it is more stable. I have also noticed I often get the message "Runtime Error R6025 - pure virtual function call" a while after I have closed the unresponsive program. I expect if you speak fluent Pooter you might know what this means!