I know it's been a minute since the thread was active, but I kind of have the same problem and was wondering what you
ended up doing to paint on the primitives.
I basically paint boxes on a surface and depending on the attributes I paint, they have a different look. So far I've used
the draw curve tool to paint curves and added custom parameters in the multiparm of the draw curve tool. This works fine,
but the more curves I draw, the more tedious it gets to go through the tabs and change the attributes.
That's why I though to use the Paint Tool to pick the attribute values beforehand and paint them onto the primitives. Now
I realize that you can't actually do that and am looking for a workaround.
Google keeps pointing me to this thread, so I thought I'd ask here.
So, do you have any new insides on this?