proyector frontal 3d

k·<c_{1}+(-1)a_{1},c_{2}+(-1)a_{2},c_{3}+(-1)a_{3}> =...
... i·<1,0,0>+j·<0,1,0>+<0,0,1>


k=( 1/(c_{3}+(-1)a_{3}) )
i=( (c_{1}+(-1)a_{1})/(c_{3}+(-1)a_{3}) )
j=( (c_{2}+(-1)a_{2})/(c_{3}+(-1)a_{3}) )


a_{i} = coordenades del observador.
c_{i} = coordenades del punt a observar.


k=( 1/( (c_{3}+d_{3})+(-1)(a_{3}+d_{3}) ) )
i=( ( (c_{1}+d_{1})+(-1)(a_{1}+d_{1}) )/( (c_{3}+d_{3})+(-1)(a_{3}+d_{3}) ) )
j=( ( (c_{1}+d_{2})+(-1)(a_{1}+d_{2}) )/( (c_{3}+d_{3})+(-1)(a_{3}+d_{3}) ) )