I just had a bright idea:
Let's define the four vertices of the tetrahedron in a 3D coordinate system and derive angles and edge lengths from their relative positions!
Should work fine, shouldn't it? Will try it tomorrow.
What method should I use to construct an irregular tetrahedron? I.e. how do I choose angles and edge lengths so that they come together as a tetrahedron? How do I formulate the restrictions that define a tetrahedron?
Only restriction I've found on the net concerns 6 of the angles:
OAB*OBC*OCA=OAC*OCB*OBA
Of course, some of angles in each triangle = 180 is another restriction. But it's not enough.
Btw, there is terribly litte info about irregular tetrahedrons on the web.
Thanks for any help!