Catenary


#1

Hi there.

Im new to dynamo and its community, so hello to you all.

I want to create a catenary line in revit, but revit does not understand what a COSH function is.

Doing a search for a catenary line, i found some help, but nothing conclusive.

I created an excel-file with a list of points wich can do the trick, but is there a more elegant way?

 

Thanks in advance,

Marcel


#2

try this:
cosh

 

 

and then: create a circle and extrude it along the catenary curve

and import into revit

cosh2


#3

Great!!

 

Thank you so much Peter.

 

Marcel


#4

hi Peter

I couldnt get it to work in a revit metric system, but my goal is to get to this interesting roof

http://vimeo.com/105157027

is multiplying/dividing by 1 mm the culprit?

Thanks,

Marcel

 


#5

marcel, i am working in metric system too.

i do not really understand your question.

what are you multiplying / dividing.

maybe show your definition so far.

for geometry manipulation (intersections): eduardo p roca’s entry “RGB Transform” on the blogs section of dynamobim is extremly helpful.

peter


#6

Peter,

This is what i have for now.

There is no line showing up.

 

Thanks

Schermafdruk 2014-09-27 21.39.22


#7

Peter

Im working in the conceptual mass environment.

The idea of dividing/multiplying by 1 mm is to get to the metric units, I followed Zach’s instructions in this little movie http://vimeo.com/11014002

Here is my .dyn file

catenary

This may be a better screendump.

Thanks

Schermafdruk 2014-09-28 08.34.52

 

 


#8

marcel,

design scripts are case sensitive!

pow = Pow and math = Math.

you can see that in your definition the Code Block delivers no result.

if you have a correct definition the command itself (like Pow) is turning dark blue

peter

 

 


#9

Peter,

its working now.

 

Thanks

Marcel


#10

BTW, you can call Cosh directly in Code Block Nodes as Math.Cosh (x)

 

2014-09-28_2243


#11

You guys are great, im getting all the help i asked for (and more)

Thanks

 

Marcel


#12

Zach, is there a manual describing the mathematical capabilities of Code Blocks?

I was already wondering if it is possible to assign number formats like

a=trunc(b)

 

peter


#13

Hi all I need to draw a catenary line with specified height and specified width how can i do that ? and is it possible to make it as a revit family?

Thank you


#14

A manual approach to determine the height. Use the slider to adjust the constant (a)

File: catenary.dyn

 


#15

Would it be possible to specify two points within a family or project file and form a centenary between them as demonstrated in the below image?


#16

Catenary between two points…

File: catenary.dyn


#17

Thanks Vikram, that script works great. I did try selecting point which are 20/10/5m apart, due to the processing Dynamo hung up. Is this script scalable within Dynamo’s?


#18

Change the second line in the code block from

x=(-l.Length/2)…(l.Length/2)…0.1; (which creates points at a spacing of 0.1)

to

x=(-l.Length/2)…(l.Length/2)…10; (to create points with a spacing of 10)

or

x=(-l.Length/2)…(l.Length/2)…#50; (to create 50 points irrespective of the distance)


#19

Thank you so much Vikram .


#20

 

Here i wanted to have a catenary with width 9 and hight 8 but i got this arc !

is there another way to find the right (a) for the top point i want.

i need the two points and the top

I think (a) is not the top of the catenary arch.

Thank you.