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Tuesday, December 15, 2009

More Revit and Math (Trigonometric Functions)

Cool little tip for roof slopes... Very much like my first Revit Calculus post where I used the arc functions to drive an angle.

As I start to get deeper into the conceptual parametric massing I am coming up with all kinds of cool tips.

Here's a great one.

When you need to constrain reference lines in order to create down stream roof slope parameters. As in 3-12, 5-15, 7-12 etc. . . . You don't want the user to have to input the roof slope by an angle. You want to input the slope as a factor of Rise / 12 as shown below. This involves a little trigonometry. Remember the old tan (x) = opposite over adjancent ?

If not have a look at the images just below.

So we know the Adjacent (12) and the user inputs the Opposite (Rise) but the trick is we have to use the 'Inverse Tangent' to get the actual angle in degrees. Otherwise all we get is the Tan of the angle, not the actual angle itself. So the correct term for Inverse Tan is ArcTan which REVIT accomodates as the built in operator atan... Continue Reading...