Hi guys! I’m new to zbrush and I’m following a tutorial. The guy makes a 3d primitive and masks it by rows. So far so good but than he just starts painting the mask on the object. When I try this zbrush says it can’t because it’s not converted to polymesh. So my question is is there a way to paint a mask on a 3d primitive. Thank you in advance 
You’re watching a tutorial for a much older version of ZBrush. Today primitives are used just as shape generators. When you have the shape you want, make it into a polymesh so that you can start sculpting it in earnest.
Thank you for. So there is no way to paint a mask on a primitive anymore. I wonder why, It seemed helpful to me.
I may be misreading your question, but although you can not brush paint a mask before you turn a primitive into a polymesh, you can mask with Mask Circle, Mask Curve and Mask Rectangle. And if you want a drawing effect, hold down CTL and select the “Mask Pen” and in the stroke selector window, select “Lasso”. You can then lasso-paint an organic mask shape.