Pilou hope BurrMan hear you :) He still think that Groboto is polygonal modeler.

I just made some research, and find what team of Groboto says:

GroBoto's Solids/Boolean engine is entirely ours. Importantly it is not a polygonal system - it uses true analytical geometry.
...actually a big deal, because we can handle subtle intersections, complexity, coincident surfaces, and a bunch of other stuff that any poly-based system would choke on... Real-Time, absolutely clean, precise, fully shaded work-mode rendering.

I don't want to launch into a pitch here (I'm GroBoto's creator & one of it's developers - 'tho the other side of my brain knows I'm really an artist).

The GroBoto Site will give you a better idea of what it's about.

Best Wishes,
Darrel

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If it is still not argument for BurrMan, I think nothing can help him :)
Just to mention as Darrel says: "Importantly it is not a polygonal system - it uses true analytical geometry."

You can read full thread here:
http://blenderartists.org/forum/archive/index.php/t-222865.html

Darrel says very clear what is Groboto and how it differs from polygonal modeling and NURBS.