[Gmsh] spline implementation

[Marek Wojciechowski]

Hi!

I'm working now on some code which uses gmsh to mesh surfaces given by single, 
closed Spline loop. However actually i do not know how the splines work in 
gmsh. For example, i expected that the script:

Point(1) = {1.0, 0.0, 0.0};
Point(2) = {0.0, 1.0, 0.0};
Point(3) = {-1.0, 0.0, 0.0};
Point(4) = {0.0, -1.0, 0.0};
Spline(1) = {1, 2, 3, 4, 1};
Line Loop(1)={1};
Plane Surface(1) = {1};

will give me a result quite close to circle. At least, for 3rd order spline 
interpolation (separately interpolated x and y with the same evenly spaced 
parameter and with periodic boundary) the result is much closer to circle. So 
may question is, how the spline curves are implemented in gmsh?

Regards,
-- 
Marek Wojciechowski
Technical University of Lodz
Department of Civil Engineering, Architecture and Environmental Engineering
Chair of Geotechnics and Engineering Structures
Al. Politechniki 6
90-924 Łódź
Phone: +0048 42 6313590
Fax: +0048 42 6313592