Forums >> Revit Building >> Technical Support >> Projected Sun Control - Parametric Support Spacing

cwsharp

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Joined: Sat, Jun 2, 2007
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I want to create a Sun Louver that attaches to a wall face... I want intermediate supports parametrically added when the overall length between supports exceeds the manufacturer's required spacing.

 I looked at the wood truss example in the tutorial, but when I have originated my own components, I can't get the family type parameters to work the way that the tutorials seem to indicate that they will work. One difference is that I used a general component wall based type which of course isn't what the turorial uses but I can't fathom why that would make any difference.

 I have considered using a railing as suggested elsewhere in the forum, but that doesn't seem to be any easier than just creating a component, and, I would like to use the opportunity to increase my family creation skills.

 Here is what I am trying to create:

http://www.armetco.com/sun/sun2.htm

I have uploaded the family file that shows what I tried to do if anyone thinks that would be helpful but it's not eve close to complete. I would like to start out with some general guidance first and upload my progress until I get it working?

Thanks.

 C#

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Mr Spot

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Joined: Mon, Jan 12, 2004
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Yes this is all definitely feasible and not really that difficult once you understand the process.

If you checkout my blog/tutorial on parametric array and nested families it explains the concept for a louvre window.

The family consists of three steps.

Create the arm/bracket family (non-hosted)

Create a non-hosted family and apply the arrays and formula as required.  Also include the mesh panel and any other non-arrayed elements. (This step isn't essential, but its much easier to do it this way)

Create a wall hosted family, nest your non-hosted family and constrain it to the wall by its origin point (the intersection of the defines origin reference planes)

Give that a try and post your results if you're still struggling and i'll diagnose any issues for you.

Cheers.

HTH.

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Regards,

Chris.

Co-Founder | BIM Consultant | Software Designer  B. Arch)

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cwsharp

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Joined: Sat, Jun 2, 2007
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OK. My startup was a hosted family. My nested bracket was non-hosted. I think it should have worked. What I couldn't do was attach a family type parameter that is existing in the parent file to the nexted bracket as was shown in the Revit tutorial on the wood truss.

I will take a look at your blog and get back to you.

Thanks.

C#

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cwsharp

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OK. What I have found so far...

I thought it would be a good idea to array both the brackets and the shades. Of course, any louver that is less than 5' long needs 2 brackets, one on each end no problem) but only 1 shade (an invalid array and a constraint conflict). I wanted to array the shades (as well as adjust their length based upon the spacing between the brackets) so that they fit between the brackets, creating the proper looking intersection of linework.

 If it isn't possible to have an array of 1 then I will go back to just using the sweep...

I also don't see an easy way to round an integer... and revit calculates anything over the next lowest whole number as an increase in the integer value, as far as I can tell. I'm going to have to construct some nested IF statements?

I'm also still struggling with the type parameters that I am creating in the nested component files. Do these become available only after I put the wall hosted family into a model? (I haven't gotten that far...)

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Mr Spot

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Joined: Mon, Jan 12, 2004
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To have revit always round up just add 0.5 to your integer parameter.

EG:  Support max span is 1200mm.

Sun shade is 5000mm long.

Formula for number of supports would be = (Length/Max Span)+1.5

= 5000/1200 = 4.16666+1 Revit would normal place 5 supports (the two ends and 3 in between) which actually exceeds the max span at 1250mm.  By adding the 0.5 Revit calculates 4.66666 and then rounds up to 6...

I also normally have an IF statement in all my arrayed families that says:

IF (Length/Max Span<2, 2, (Length/Max Span)

This tells revit two always have a minimum of two supports.

HTH.

-----------------------------------

Regards,

Chris.

Co-Founder | BIM Consultant | Software Designer  B. Arch)

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cwsharp

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Joined: Sat, Jun 2, 2007
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Well, it should be obvious by now that I'm a novice at this!

That tip certainly helps, but maybe I'm missing the obvious.

I need two supports (which I can get the array value of 2 for easily enough) but only 1 screen.

So, arraying the screen (which has a variable length) and getting two supports (which have a variable spacing) means that I need to include an if statement that sets the array value only when the number of screens exceeds 1 and then ignores supplying an array of 1 somehow. That's where I get in trouble... by applying an array to the shades, then I can't figure out how to ignore the array and I can't have an array of just 1 shade, as far as I can tell. I can work around this by simply creating two components... one that is a sun screen up to 5' long and one that is for a sunscreen over 5' long... eliminating an array from the fisrt component. I wanted to be more elegant than that, but once I couldn't use LISP, then I stopped being a good CAD developer <grin>.

Thanks for all of your help.

C#

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cwsharp

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I realized while working on this some more that I am after something slightly different than I think you are describing...

I don't want to use type parameters unless I have to... I would like to use instance parameters. This would allow me to create different length sun louvers. What has to happen is that up to 5' i would have one shade and two brackets. For every 5' (or portion thereof) after that, I would add a shade and one bracket. I would space the brackets evenly over the length of the louver as long as it doesn't exceed 5' between brackets.

If I use type parameters, as I understand it, I would have to create a new family type for each louver lenght that I put on the building. I would prefer to use on family type to do all of the louvers on the building.

Creating a horizontal curtainwall is probably how many have done this...

What do you think?

C#

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