REVIT dimensions can take formula like excel

[Chirag Mistry]

Did you know REVIT dimensions are smart to take in formula, eg: =14'-2', it will put in 12'.

This works for any of the blue dimensions that you can type in...pretty cool...huh !

[aaronrumple]

...been that way since the begining of time.

Note that this is true for any field you type in a dimension - not just dimension strings. This includes dialogs and schedules.

[Steve_Stafford]

...This works for any of the blue dimensions that you can type in...pretty cool...huh !Indeed it is...and it's worth bring it up from time to time, since it's easy to miss.

[iru69]

One of those things that I was vaguely aware of, but have never used... what are a couple of examples where that's useful?

[gravelin]

Is it possible refer to a project parameter or to a constant (PI) ?
I never could do It .

[Steve_Stafford]

One of those things that I was vaguely aware of, but have never used... what are a couple of examples where that's useful?My most common use for it has been dealing with metric and imperial units. Since I'm most familiar with imperial units I often will enter the following to convert 7'-0" to millimeters:

=25.4*84

...then I'll round up (to clean up the metric value) the dimension once I know the metric equivalent.

Another is when you know the overall length or space available and you want to move an object to the middle, like a door or window, with the temporary dimension adjusted to have a witness line at the door centerline and the other end on the appropriate edge of a wall enter:

=15' 3.5" / 2

[Steve_Stafford]

Is it possible refer to a project parameter or to a constant (PI) ?
I never could do It .No it isn't...not in a project...

[gravelin]

No it isn't...not in a project...Does it mean that it's possible the family editor ?
I know it's possible in the parameter dialog box
But in a dimension ?

[Steve_Stafford]

Does it mean that it's possible the family editor ?
I know it's possible in the parameter dialog box
But in a dimension ?Sorry, no...didn't mean to imply that. You can use a parameter in a formula as you say, within the family types dialog.

You can enter a value like:

=Atan(4*5)

Revit doesn't recognize pi

[LRaiz]

pi = 4 * atan(45)

[gravelin]

pi = 4 * atan(45)Is there a technical reason to not have PI as a constant ?

[hand471037]

One of those things that I was vaguely aware of, but have never used... what are a couple of examples where that's useful?

OK, so you want a wall 1/3 the distance away from something?

Click the wall, then drag the grips of the temp. dim string so that it points to that something.

Then click on the dim. value, and simply put a '=' in front of it, and a '/3' behind it, and hit return.

I do stuff like this all the time. It's a huge help, esp. when the values for things are really strange, like figuring out thirds of 4' 5" 9/64"...

This is one of my (many) personal favorite things about Revit.

[ita]

Jeffrey that is very neat. What other gems like that do you have?

[gravelin]

Another case is to calculate the actual tred depth for a circular stair.

If you want to create 10 treads along Exactly 180° (picture #1)
you need to calculate : (Radius * PI) / nbtread. (picture #2)

PI as a constant will be so helpful here...
because you can't use the PI constant, you obtain an error message about accuracy (picture #3)

[Martin P]

I use it a lot when pressing Eq on a temp dimesion string doesnt move things the way I want or gives me an error message


Select the object you want centered. The 2 different sizes wuill appear as temp dims - say 100 and 200 (so the Eq dim would be 150)

I edit one of the temp dims like this
=(100+200)/2



I also find it useful when drawing up something from survey notes - I can do

100+2000+325+........... and I can see on screen before I press enter that I have added all the values

[hand471037]

Jeffrey that is very neat. What other gems like that do you have?

Oh man oh man, too many that I have time to list here...

But here's a silly one that I love for presenations:

Glass remains transparent, even on the sheet, even when you overlap stuff... I've used this on a number of occasions...

[bclarch]

OK this is what I get from the Google calculator. 4*atan(45) =6.194.... This is approximately 2pi. What's up with that?

[bclarch]

Did a quick search and turned up this page (http://www.newdream.net/~sage/old/numbers/approxpi.htm) on the web. The fraction 355/113 approximates pi to six decimal places.

[LRaiz]

bclarch,
I made a mistake in my previous statement that pi = 4*atan(45)
It is easy to see that the correct formula is pi = 4 * atan(1). This is because tangent of 45 degree angle (pi/4) is equal to 1.
tan(pi/4) = 1 ----> pi = 4 * atan(1) and any calculator (except Revit) will confirm it.
However this formula can not be used in Revit because atan function in Revit provides an extra favor. Instead of returning result as radians it converts it to angles. So instead of getting pi the formula would produce 360 degrees.

For the time being a value of pi provided by Windows calculator 3.1415926535897932384626433832795 will have to do.

[iru69]

OK, so you want a wall 1/3 the distance away from something?

Click the wall, then drag the grips of the temp. dim string so that it points to that something.

Then click on the dim. value, and simply put a '=' in front of it, and a '/3' behind it, and hit return.

I do stuff like this all the time. It's a huge help, esp. when the values for things are really strange, like figuring out thirds of 4' 5" 9/64"...

This is one of my (many) personal favorite things about Revit.
This and all the others that people suggested are pretty cool... good to know.

[gravelin]

Another case is to calculate the actual tred depth for a circular stair.

If you want to create 10 treads along Exactly 180° (picture #1)
you need to calculate : (Radius * PI) / nbtread. (picture #2)

PI as a constant will be so helpful here...
because you can't use the PI constant, you obtain an error message about accuracy (picture #3)
No more error If you choose 10 decimales in project units.

Here is all you want to know about PI
http://www.pi314.net/

[hand471037]

This and all the others that people suggested are pretty cool... good to know.

The first 3D software I got really into, and used professionally, had this feature as well.

In Caligari and later Caligari Truespace you could open a Properties box for objects and points and vectors and such, and it would report the X-Y-Z coor'ds, and you could just enter in math functions (just like Revit) and have it take.

I grew so used to that, and while you could kinda do it in AutoCAD too (it wasn't nearly as simple), I've always wondered why it isn't just a default in 3D software for it's so useful...