Greg Dykstra is a sculptor and character designer who has worked on several major animated features. During the production of Up by Pixar, Dykstra made a “design sculpt” of the character Carl (Romano 2015). Character designer Lou Romano describes using this model to experiment with color and lighting:
I painted and photographed this sculpt to see what Carl might look like in different lighting. Bryn Imagire (Shading Art Director) painted other sculpts exploring healthier complexions. She also made models of the house, plants, and rocks, to impart a tactile quality to the digital work.
http://louromano.blogspot.com/2009/05/art-of-up_3697.html

Lou Romano also made a “rough desktop diorama” that depicted a scene from the Up screenplay. This was used as a tool for experimenting with color, effects, and compositions. Romano (ibid.) explains:
I made these figures then photographed them on my desktop. The smallest figure is the size of a grape. It was a way of arranging and finding interesting compositions in 3D. Effects were added in Photoshop.
Ibid
The figures in the dioramas (below) are beautifully blocked out as simplified geometric shapes and serve as enigmatic representations of the characters that they predict.

http://louromano.blogspot.com/2009/05/art-of-up_3697.html

http://louromano.blogspot.com/2009/05/art-of-up_3697.html

http://louromano.blogspot.com/2009/05/art-of-up_3697.html

http://louromano.blogspot.com/2009/05/art-of-up_3697.html
I love the energy in these rough diorama tests by Lou Romano. I like to think that after they were made based on the script, they might have returned inspiration and even catalyzed iterations to subsequent drafts of the script. That’s certainly my aim when I make sketch models. While I want them to represent aspects of the script, I also want them to inspire and influence the script in a way that only a tangible object can.