[pstricks] 3D clipping - again

Jean-Côme Charpentier Jean-Come.Charpentier at wanadoo.fr
Fri Nov 4 06:38:39 CET 2005


Pedro Jorge Caridade wrote:
> Thanks Manuel
> It is was that what I want. Now for a more tricky example, if the
> cutting plane is not at the middle of the paraboloid? 
> 
> Hum, probably is not possible to draw it. 

Surely it's possible:
   * a paraboloid P is a polynom like x^2 + y^2 = kz
   * a cutting plane C is a polynom like ax + by + z = h
Then P \cap C (if I don't mistake... not sure):
   (1/k)x^2 + ax + (1/ky^2 - h + by) = 0
for each y, you have to solve an equation (degree 2). Even I mistake 
myself, I'm sure that you obtain an equation of degree 2.

Now, there is a rather long code to write :-)  But no hard maths (no 
hard TeX/PS too, just long).

   Jean-Côme Charpentier




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