AC curtain panel as measurement tool

[jbenoit44]

Hi RFO,

I wanted to share here a use of Adaptive Component as a tool. Sometime you need to schedule that particular area, and you just can't, for many good reasons. In that case, I use an AC curtain panel with 4 points, then I schedule it. and it gives me the accurate area I wanted.

At first glance, when using a simple 4 points AC CP, with only a surface in it, you will have a surface value computed by Revit, but it will be only the half of the correct area. weird, but with a simple calculated value, you get the correct answer. but it's a CV, not always good enough.

In the attached family, I have used a specific formula, named BRETSCHNEIDER's formula. it returns the area of any quadrilateral in a shared parameter, much better than a calculated value IMHO.

this AC is placed with 4 points, either on a plane or a face.
beware that in some cases, when rehosting the AC, the computed area is wrong. don't know why. my advice would be to avoid rehosting this family.

Hope it helps, hope you like it!

Have fun!

PS: looks pretty similar to some great families from Zach Kron, but I baked this home ;-)

[Dave Jones]

Hi RFO,

I wanted to share here a use of Adaptive Component as a tool. Sometime you need to schedule that particular area, and you just can't, for many good reasons. In that case, I use an AC curtain panel with 4 points, then I schedule it. and it gives me the accurate area I wanted.

At first glance, when using a simple 4 points AC CP, with only a surface in it, you will have a surface value computed by Revit, but it will be only the half of the correct area. weird, but with a simple calculated value, you get the correct answer. but it's a CV, not always good enough.

In the attached family, I have used a specific formula, named BRETSCHNEIDER's formula. it returns the area of any quadrilateral in a shared parameter, much better than a calculated value IMHO.

this AC is placed with 4 points, either on a plane or a face.
beware that in some cases, when rehosting the AC, the computed area is wrong. don't know why. my advice would be to avoid rehosting this family.

Hope it helps, hope you like it!

Have fun!

PS: looks pretty similar to some great families from Zach Kron, but I baked this home ;-)

well done Julien! Thanks for posting. I had never heard of a Bretschneider's formula before...interesting stuff!!

[Alfredo Medina]

That formula is very precise. However, it's kind of an extreme solution. It takes considerable time and work to make that panel with all those reporting parameters and the long formula. In absence of such a panel, a simple curtain panel family with a box of 1 mm of thickness, with no parameters and no formulas, will report the same area, or a very approximate value, compared with the complex panel, depending on the number of decimals of the area units. As the number of decimals increases, the complex family will prove to be more precise than the simple panel. But if we don't need several decimals of precision, the simple panel reports an area that is good enough.

Yes, Revit shows an area of 2 square meters for a flat panel of 2 m x 2 m. That is wrong and unexpected. But at least we can fix it by adding a minimum thickness to the panel, such as 1 mm. Now the area parameter will show the area of all the surface of the panel, plus half the area of the side faces, which in this case will be 4.004 square meters; really strange. But, bottom line is that for a schedule of panels with a default precision of 2 decimals for area, both the simple panel and the complex panel will show the same result of 4.00 square meters.

[gaby424]

well done Julien! Thanks for posting. I had never heard of a Bretschneider's formula before...interesting stuff!!

Than maybe you want for triangles too

S=sqrt(p*(p-a)(p-b)(p-c))

where
p=(a+b+c)/2
a,b,c = triangle`s sides

Heron's formula.

With this formula you can find the surface of any poligon with any shape because a poligon can be splited with reported length parameters in a finit number of triangles and you can make the sum (with a formula) of the triangle's areas.

[jbenoit44]

Yep Gaby, that was exactly my starting point. But I discovered that Heron's formula doesn't always work, with triangles where a side length is very small regarding the other two. Some Google search show me why, and that way try 2 was the good one.
Alf, I agree with all your points. Computed area is such a weird thing. Works well in most cases with Revit objects though. But I was happy with this formula, just wanted to share ;-)
Building this family is a good exercise, not as simple as it looks at first glance.

[gaby424]

Nice find Julien. Never thought a school learned formula can fail some time lol

[jbenoit44]

Attached file fixed, points having wrong orientation.