while in paperspace, activate your viewport by double clicking in it then at the command promt type vpmax. then restore layout, that solves the problem.
This post is over 2 years old - what version of C3d are they refering to, and which are you refering to? Has this been resoloved in the newer releases? I understand the C3d 2007 had many problems that no longer exist in the versions that most here are now using (10, 11 &12).
Reid
I did see that this post was old but unsolved, this problem arose in c3d 2008 and i encountered in c3d2012. I recently upgraded from c3d 2010 to 2012 about two weeks ago. I had created a surface from points and breaklines in 2010 some in January, i then decided to take this project in 2012 and everything seemed great, but everything that the original post encountered I encountered it. One of the greatest things about c3d 2012 is it doesn't crash when working with large surfaces or a multitude of surfaces in one drawing. So c3d 2012 is still the way to go.
Jessy