Curvilnear perspective

I've always been fascinated by Albert Flocon's book about Curvilinear Perspective.

[source]

I started the article in the french wikipedia and I've searched for a long time how to generate those figures. The solution was rather simple simple: For a point with the 3D coordinates:

(x0,y0,z0)

. Then, in a curvilinear perspective

dist=sqrt(x1^2 + y1^2 + z1^2)

x=x1/dist
y=y1/dist

I can now generate my own drawings! :-)

Using a curvilinear perspective...
>
... or using a classical vanishing point.

That's it,

Pierre