It might be a plugin clash, and until you've tested as Dave suggests we won't know... but I can't envisage any 3rd party code that might do this - so I suspect it's a Sketchup/OpenGL/graphics-card issue - have you tried reinstalling/repairing Sketchup ?

Glad it worked, but that's the only way I know of - if you do find another way, let us know!

oh. one of those. yeah, you can't do it solely with standard sketchup inferencing. i bet there are quite a few tricks out there but my own go to is similar to yours except i'd use TIG's extrude edge by vector to make the vertical face.. (select a line, extrude it up (or down) but keep it as a group for easy deletion when your done with it.. draw the vertical line then delete the group). i guess if i had a lot of these on one drawing, i'd consider draping all the criss-cross lines (sandbox tools) onto a flat plane which would show you where the intersections are.

@wozabee said: It works just absolutely spot-on now!! ...now to re-learn some Keyframe animation & such, and see if I can put this chap through his paces. Thanks so much again Kwok! Woz, you're welcome. Would love to see the animation, when you are done.

BTW, here's the link to Kwok's "Key rotate" plug-in: http://forums.sketchucation.com/viewtopic.php?t=28086 Thanks for the pointers so far Kwok! Woz

Thank you, Thank you, Thank you, Thank you, Thank you, Thank you!!! Hopefully... this'll solve my woes. Cheers Honoluludesktop, Woz