inches / inches = inconsistent units

[kgatzke]

I want to enter a height value from standard pitch notation like 1/4" for roofs, etc. and get back an angle value to slope part of a family.  I get the right angle if I put in 'atan(12/.5)' but everything I try to do to replace .5 with a parameter based on pitch results in some kind of units error.

[kgatzke]

Nevermind, I see what I did wrong.  "Angle" was created as length.

[kgatzke]

Nope, still getting an error.  It calculated the angle correctly and then give me this...

[rodrigo.bezerra]

Since Revit works with distinct kind of parameters (such as angles, integers, area, length), the outcome of an formula must be exactly what a parameter expects to be.
Ex. 1 meter x 1 meter = 1 sq meter. So, if the result of my formula is an area, my parameter must be an area parameter.

"But I want the value, not the meaning of it". Well, then you have to add to your formula a math way to solve it. Ex: (1 meter x 1 meter)/1 meter = 1

This is my guide for formula issues.

[barthbradley]

You have another FAMILY TYPE that is erroring out. Not the one showing in your screenshot. 

1/2" tapered - 2" thick

[kgatzke]

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@barthbradley wrote:

You have another FAMILY TYPE that is erroring out. Not the one showing in your screenshot. 

1/2" tapered - 2" thick

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Which was probably set to 0 by default resulting in a divide by zero.   Problem was solved however by modifying a similar where everything worked.  No angles were used in that one.  The pitch was created by the difference between two reference planes and a boring ratio formula, all units in length.  Thanks.