Minimum Area Relating to User-Input Width

[Anonymous]

Hello,

I am student working on a custom skylight family where the Width can be specified by the user and the Length relates to the given value by 1.5 (Length = Width * 1.5), with no max Width. However, a requirement of the skylight is the minimum possible area is 1.0 sqm.

How do I write an IF formula where the user-given Width relates to the minimum required Area?

I tried a formula but it apparently "cycles":

Width - IF (SkylightArea < SkylightAreaMin, 816 mm, Width)

I hope someone recognizes my intention. If not, I can answer any other questions to clarify the situation.

Thanks,

MC

[constantin.stroescu · Accepted solution]

use an additional parameter ..W in my example...

[Anonymous]

Hi @constantin.stroescu,

Thanks for the suggestion. It helped me with the full development of what I wanted to do.

Just needed to adjust the length to reflect the "* 1.5" factor.

I know my Parameter names are long, but I need to add more "lengths" and "widths" to this.

Sincerely,

MC

[barthbradley]

“Length” should actually be the evaluated parameter. Replace “=Width*1.5” with this formula:

= if((1.5 * Width) > Skylight Area Min / Width, Width * 1.5, Skylight Area Min / Width)

[barthbradley]

Yep; not much to it. Or, am I misunderstanding?  

[barthbradley]

[Anonymous]

Hi @barthbradley,

I tried to input the formula but it doesn't work as I want it to.

The premise is to have a minimum area of 1.00 sqm, maintaining x as the shorter side, and 1.5x as the longer.

Thanks for the suggestion, I tried it. Unfortunately, it's missing the function where it changes Width to an appropriate number where it maintains a relationship with Length with a factor of 1.5. Example, I entered 600 mm as Width, and the formula gave me 1 666.67 mm as Length. Which is not 600 mm * 1.5. 

With lots of tweaking, I think I'll stick to what I have come up with. It may look messy but I think this is the most stable I got. Notice how it overrides the manually entered value of 600 mm:

-MC

[barthbradley]

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@Anonymous wrote:

Hi @barthbradley,

Example, I entered 600 mm as Width, and the formula gave me 1 666.67 mm as Length. Which is not 600 mm * 1.5. 

---

Yes, it returns 1666.67 because the minimum skylight area is 1.0 sqm.  600mm*1666.67mm=1.0 sqm (the minimum allowed). 600mm*900mm=0.54 sqm (about half of the minimum allowed).  I guess what you are saying now, is that you want a formula to automatically calculate BOTH the Width and Length Parameters,  which is virtually impossible since the evaluation for each would need to be based on Length*Width (e.g. "Skylight Area").  That's a circular reference. You would need a DeLorean Motor Car with a Flux Capacitor to be able to pull that one off.   

[Anonymous]

I guess that's how my new formula involved two more parameters (SkylightWidth, SkylightLength) which are attached to the model's dimension.

"WidthEntered" and "LengthEntered" would be the user-defined parameters.

It doesn't cycle since the user-defined data is merely input (i.e. WidthEntered), and the processing and output are a different parameter (i.e. SkylightWidth).

Also, another requirement is to maintain a 1:1.5 proportion between the two dimensions. That's why 600:1666.67 doesn't work.

Now, I'll be off to grab a Pepsi Perfect.

[barthbradley]

@Anonymous: I got a another suggestion for you that maybe you and your team will like.  Two words: "TYPE CATELOG". Are familiar with them? They are all the rage with BIM content manufacturers these days.  Keeps the families streamlined and user friendly.  You may even want to investigate LOOK-UP TABLES.  I can see 'em  working here. 

FWIW. 

[barthbradley]

Not only a Skylight Area Minimum, but a Width Minimum based on an Aspect Ratio as well (e.g. 1.5:1).   Note: "README" and "Minimum Width" and "Aspect Ratio" are not necessary parameters if simplicity is the aim.