OpenMesh makes use of the LGPL v3 with the following exception:

As a special exception to the GNU Lesser General Public License, 
you may use any file of this software library without restriction. 
Specifically, if other files instantiate templates or use macros 
or inline functions from this file, or you compile this file and 
link it with other files to produce an executable, this file does 
not by itself cause the resulting executable to be covered by the 
GNU Lesser General Public License. This exception does not however 
invalidate any other reasons why the executable file might be 
covered by the GNU Lesser General Public License.
