i have to agree with pjz99.  but i'm also generally pessimistic, too. 

this is what you're basically saying: an artist will paint in distribution and you'll provide a brush that will then fill in according to that distribution and show them the effects of painting from minutes to hours after painting.  can you imagine Photoshop working that way?  my guess is that it will take a good deal of trial and error before the effect is what the artist intended.