>>I don't know, but maybe you can try also MathMod, the successor of K3DSurf...:

https://sourceforge.net/projects/mathmod/<<

Good tip, I´ll have a look, the export as curves is a good feature>>Not to be off-topic, but here's a little doodle i did yesterday, just exported the splines from
Math Modeler from Shade and then imported them into MoI and made a solid out of them.
After that processed in ZBrush and texture painted in 3DCoat.<<

Cool crossover experiment. Did it take long for you to get familiar with Zbrush. Cinema4D
has sculpting tools but they are not as near as powerful as Zbrush ..