Draw sharp edges

Hi…

Do you know any program with source code that allows drawing sharp edges please?

Many thanks

Are you talking about hard/soft edges on polygonal models? where the normal vectors are either set to give a flat shaded effect, or cacluated as averages between faces to give a smooth shaded effect?

Yes… but instead of controlling the shading… I’d like to draw the edges shared by two faces which angle between them is superior to an threshold… any example?

Yes… but instead of controlling the shading… I’d like to draw the edges shared by two faces which angle between them is superior to a threshold… any example?