This demo use SoLassoScreenDrawer and SbExtrusionGenerator to generate extruded shapes. These extruded shape are then written to dataSet using current slider value. Contrary to CSGClippingGroup demo that just clip dataSet during rendering, dataset is modified by editing. Use the selection mode (arrow) and draw a lasso on screen. Release mouse to finalize the lasso.
SoDataSet, SoLassoScreenDrawer, SbExtrusionGenerator