Formulas

[TV98001]

Does anyone have a good suggestion for websites and or learing material to help teach some understanding and implementation of formulas withing parameters for use in families?

[mdradvies]

start by reading this thread. You might want to check the autodesk wiki too. After that, just start using them...

A few sidenotes:
- Remember that Revit is sensitive to the Units. Length x Length is Area. This seems logical, but in some cases it's not that obvious.
- Annotation of formulas is somewhat similar to Excel. So you might want to try the formulas there before using them in Revit (easier when starting)
- type parameters can't be driven by instance parameters. This might seem weird but think about it: a type parameter only changes when you create a new family type. An Instance parameter can change any time you want it to.
- Revit cannot choose. Weird remark? I often get this question:
"I have a window divided in two panels. Why can't I dimension a total width, left panel and a right panel?". Well, what if you change the total width? What panel get's bigger? Think about what you want to know/do, and what logical sequence of steps makes this happen.

[TV98001]

So I have been reading through some info. and doing some tutorials but I need to figure out how to constrain some leader lines to the edge of a beam system. Not the lines showing the direction of the framing elements in the system but additional lines showing the extent. I have started to try and modify the generic beam system tag but have not been able to figure out how to keep the extent lines constrained to the edges of the beam system. I could use some help.

[Alexander_J_Hicks]

I'm pretty sure the Revit Wiki actually used the same post for their formulas help. It credits the forum on it lol.