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How to Calculate the length of a rafter????

Anonymous
Not applicable
I have taken the Archicad Roof Maker library and copied it to my own custom library. I have removed the calculations that were created by the part already. I want to create a variable similar to what has already been done, but I want the calculation to show up in the new variable using a parameter script so that I can use it in a IF THEN statement in the properties script. I have thought about pythagora's theory and SOHCAHTOA, but I cannot find a formula that will place the calculated value in the varible I have created. Should the variable be a text, integer, or a real number? Any ideas would be greatly appeciated. Thanks.

Barry
4 REPLIES 4

Steve Jepson
Advisor
Like this?
lenght of rafters.png

ArchiCAD 25 4013 USA - Windows 10 Pro 64x - Dell 7720 64 GB 2400MHz ECC - Xeon E3 1535M v6 4.20GHz - (2) 1TB M.2 PCIe Class 50 SSD's - 17.3" UHD IPS (3840x2160) - Nvidia Quadro P5000 16GB GDDR5 - Maxwell Studio/Render 5.2.1.49- Multilight 2 - Adobe Acrobat Pro

Anonymous
Not applicable
I am not sure of how it should be programmed in GDL, but the equation you are looking for is as follows;

Rafter length (along slope) = Rafter length (on the flat) x Secant of pitch
where Secant = the inverse Cosine (1/Cosine)

or more simply

Rafter length (along slope) = Rafter length (on the flat) / Cosine of pitch.

For example to work out the rafter length of a rafter spanning 3.0m at a pitch of 15 degrees

RL = 3.0 / Cos 15

I hope this helps

Steve Jepson
Advisor
I see my last post did not have the attachment.
Is this what you want?
Beam with length on slope.jpg

ArchiCAD 25 4013 USA - Windows 10 Pro 64x - Dell 7720 64 GB 2400MHz ECC - Xeon E3 1535M v6 4.20GHz - (2) 1TB M.2 PCIe Class 50 SSD's - 17.3" UHD IPS (3840x2160) - Nvidia Quadro P5000 16GB GDDR5 - Maxwell Studio/Render 5.2.1.49- Multilight 2 - Adobe Acrobat Pro

Anonymous
Not applicable
I'll give it a try. Thanks.

Barry Halloran

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