Thanks for your Replies 
But the "tricky part", the algorithm (Delaunay or something like this) is no problem for me.
In SketchUp is there something like GL_TRIANGLE_FAN or T_LINE_STRIP? Do I just have to loop the code I wrote in the first post? Or are there possibilities to do it a simpler way? To reduce code? Do it faster?
Hackbard_C
Doing it myself is the better way... because maybe I need this for my master-thesis, however ouf course an existing script (with reference/author) is possible.
But I need the source code too, so that I can adjust it to my needs.
Ok, I'll start a thread at the ruby Forum, just thought of beeing a newbee in sketchp 
What I want to do? Making a Hull.. mhm.. maybe comparing with a terrain... there is a grid and each point has a specific height... and i have to triangulate this grid, but the grid I have is not a regular one, the points aren't equally distributed.
i have points p1, p2, p3,... pN... and I know (p1,p2,p3) has to be a triangle, (p2,p3,p4) has to be a triangle.. and so on. I dont know how to do this with the Sketchup Api
edit
Ah, someone moved this topic - thanks!
/edit
Hello,
i have a plenty of points and want to create a surface with the sketchup ruby api. How do i do this? I dont get a "nice version"..
# points will be read from a file... pts = [] pts.push([0,0,0]) pts.push([0,9,0]) pts.push([9,9,10]) my_face = Sketchup.active_model.entities.add_face pts f_material = Sketchup.active_model.materials[0] f_material.color = "green" f_material.alpha = 0.5 my_face.material = f_material
Of Course, this works, but how do i appendd another polygon? I have to loop, but creating evertime a new face? Actually... faces, polygons, entities.. where are the differences? What about hierachy?
Programming in general is no problem, but i dont get the way of thinking in sketchup in my brain.. maybe there is a good tutorial? (I just found ruby-tutorials (i dont need) or sketchup tutorials (helpfully, but i want to use ruby with it!) and [0] is quite poor...)
Regards,
Hackbard_C
[0] http://code.google.com/intl/de/apis/sketchup/docs/tutorial_geometry.html