Civil 3D is not responding when switching between Model tab and Layout tabs...

Hi everybody... This is something that we have had seen a lot lately (Civil 3D is not responding when switching between Model tab and Layout tabs). It can happen for multiples reasons, a corrupted drawing, video card issues, network problems, to name some of them.

Every one of you is unique on your own environment, even if you have to exact computer they can behave differently and what it could work for you it may not work for someone else...

Here are some things that you can try.

System Variables

1. Set the WHIPTHREAD to 3, this SV controls whether to use an additional processor to improve the speed of operations such as zoom, redraw or regenerate the drawing.

One thing to keep in mind, when multithreaded processing is used for redraw operations (value 2 or 3), the order of objects specified with the DRAWORDER command is not guaranteed to be preserved for display "but is preserved for plotting".

Go to Options -> System tab, under Layout Regen Options and select "Cache model tab and all layouts", click Apply and OK; or set the LAYOUTREGENCTL to 2. 

This option regenerates the drawing the first time you switch to each tab, the display list is saved and regeneration is suppress when going back and forward between them...

Hope this will work for you...