burnin:
Thanks for the advices, I can achieve the desired look with them. :)
maru:
Yes, the geometry is simply black and white, in front of a white background, this is why you cannot see the contours of the hemispheres that build the form up.
My question is towards the red highlighted part, if there was a way to have this effect with Corona, without any postproduction.
(Maybe this should go to the general CG topic, I don't know.)