CGAL users discussion list

Jonas Schild wrote:

> Furthermore, I don't understand how ccw(int) on the triangulation 
> structure is supposed to work regarding finding the correct orientation 
> thus the normals are pointing outside the volume.

Hi Jonas

There is no ccw function in 3D.

You can look at the beginning of the User manual of 3D Triangulation 
Data Structure, you will find the explanation of the orientation of cells.
You can see there how to get vertices of the facet opposite to vertex i 
in a cell in an ordered way (be careful, it depends on the parity of i).

Also, in case it may help, in the reference manual of 
CGAL::Triangulation_3 you can find

Triangle          t.triangle ( const Cell_handle c, int i)
		Returns the triangle formed by the three vertices of facet (c,i). The 
triangle is oriented so that its normal points to the inside of cell c.
The typedef at the top of the page tells you that the type returned is 
in fact a CGAL::Triangle_3, if you are using the CGAL Kernel as traits 
class.

Best regards
        Monique Teillaud