Incorrect answer - Cut Planes

the following question was shown and answered in my opinion incorrectly. this should likely be 3’ above finished floor, or 4’, but never 6!

An architect is setting up a building information model (BIM model) for a new project, and must establish the plane at which floor plans will be cut through the model.

How high above the floor is a typical “cut plane” for a floor plan?

3 feet

Incorrect. At this height, some windows would not be shown (if they begin at 42" above the floor, for example).

6 feet

Correct. This height allows the floor plan to show windows, cabinetry, doors, and all other pertinent information that should be included in a floor plan. Any higher or lower height would potentially not cut through these pieces of information. All information above this plane is typically shown on a reflected ceiling plan.

1 foot

Incorrect. At this height, no windows except floor-to-ceiling windows would be shown. All casework (which is typically about 3 feet tall) would be shown, potentially creating a confusing drawing.

8 feet

Incorrect. 8 feet would be too high to cut through doors (which are typically less than 8 feet tall) and some windows.

Welcome to the Black Spectacles Community @DBerger! Thanks for writing in with your question.

This is a great example of selecting the best answer of the choices provided. While 6 feet might be a little higher than you’re familiar with in practice, it is the best choice of the others provided (1 foot, 3 feet, 8 feet). I think we could easily eliminate 1 foot (too low) and 8 feet (too high); so you’re left to decide between 3 feet and 6 feet. As mentioned in the answer explanations, 3 feet may not capture some windows. 6 feet, however, should capture all floor plan elements as they would all typically fall within this height range.

Sometimes the ARE oversimplifies concepts and tests you on your basic understanding/application. Here, you are asked about a cut plane, so you should know what a cut plane is and what purpose it serves in relation to floor height.

Hope this helps!

Kiara Galicinao, AIA, NCARB
Product Coordinator
Black Spectacles