I'm not a teacher, so I can't answer your question directly. However, I was a student who had to build lots of models in set design classes, so here are my thoughts.
A set model only has two purposes for existence: one is to clearly illustrate the design concept to the director, choreographer, and other folks involved, and the other is to clearly illustrate the design concept to the scene shop. Somewhere in there the model is also often used to pitch the design concept to the director and/or producer.
Because of this, when we did models, the professors looked for two main things. First and foremost was whether the design served the story and the director's vision of it. If it didn't, he or she was very clear about it and we got a low grade, regardless of how well executed it was.
Then there was the execution itself. If we wanted to put, say, a staircase in the model, it was expected that we would make it look exactly like we wanted the real staircase. Otherwise the illustration was not accurate and clear to those working on the real set. If we put texture on a surface, it was expected that we wanted the texture to look like that in the model, which also meant scaling the texture correctly. Same for paint colors, drapes, and other elements.
I pointed this out to a student designer at a recent high school theate festival. Her concept was fine, but the execution was not good: she took too many shortcuts. I explained that a director would figure that the set would look like the model, so he or she would take up a lot of time asking about this detail and that detail, and I'm not kidding: "Does that curtain really have to be wrinkled?" "Why is the edge on the floor shaggy?" "That's not what the chair will look like, is it?" "That texture looks like it's two inches thick; is that how it will look?" "Are you really going to put large pennies on the floor?" And so on. I've actually heard all this, and much more. :-)
Nothing wrong with asking questions, but these talks can eat up a lot of people's time, especially when you have to explain verbally how things will look different on the real set.
Shops are even worse: they will sit here and argue with you about why the model and the drawings don't look the same, and which one is correct, and how they're supposed to know that. In union shops, that can cost a lot of money.
Again, I don't know how to answer your question directly, but I hope this has given you a few thoughts.
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George F. Ledo
Set designer
www.setdesignandtech.wordpress.comwww.georgefledo.net