Hi Tom,
I was curious if there was a reason why you had the use of precompiled headers turned off as well as minimal rebuild option.
A full release version rebuild took 105 seconds.  After changing the project file to use precompiled headers, it went down to 11 seconds.  In order to do this, you will need to change the
#include "..\stdafx.h"
to
#include "stdafx.h"
Minimal rebuild will cause only the file that you modified to be rebuilt when compiling rather than a whole slew of files.
In all of the Lib3D source files.  I'll see if I can upload the vcproj file into the group.
Eric

Tom,
I put my vcproj file into the Eric Sanders folder for you.  This was modified from a stock install of v433c so should be a drop in for your version of KMotionCNC. 
Eric