Interesting tool, Sascha! I'm experimenting with alternative volume representations in game engines so this comes in handy.
I think I found a bug on my computer where the model viewport shows the model from the front, but I can't move anything around. I had to use preview which is annoying due to the noise on the model..
Also, why do splines not support non-uniform scaling? I couldn't figure out how to make a characters my characters back arch. I was looking for some NURBS-way or sth along that. Some way to define organic complex surfaces.