Dependent reference planes to create a sloped arch bridge

[D.DI]

Hello all !

I have to create an arch bridge with the cables attached(picture 1 and 2) ; I did it, but I would like to parametrize it a bit in case any changes will appear.

The model was created in Revit so it can be exported in SCIA for structural calculation. In image 3 you can see the cable is modeled in 2 pieces (PIECE 2-green and PIECE 3-orange). The cable is connected to the structural axes (red for the arch bridge & blue for the base foot) using PIECE 1 (black).

As D1 might vary PIECE 1 will change and the whole reference plan of PIECE 2& PIECE 3 will change

As D2 might vary PIECE 2 & PIECE 3 will change their lengths

I managed to do it, by using model lines drew in the plan of the arch bridge and then offset them a the good distance. If anything will change, I will have to restart again

Therefore I was thinking to use 2 reference planes (dependent on the main plane of the arch bridge)to control D1 &D2 and the PIECE 1 & PIECE 2 & PIECE 3 to change automatically the position/length. But I can’ manage it. I tried to create a plan parallel with the main plane of the arch and add a dimension between them, but when changing the distance, the arch would be the one moving, and PIECES are not changing lengths

Do you have any suggestions? Thanks

1-section2-elevationImage 3

[barthbradley]

Why not do it with a parametric truss family?

...I'm certain the "flexing" you are trying to parmaterize can be done using trigonometric formulas.

https://www.revitforum.org/tutorials-tips-tricks/1046-revit-formulas-everyday-usage.html

[D.DI]

thanks for your answer. 

But how do you create the perpendicular elements on the webs (PIECE 1 -black)?

[barthbradley]

As nested components loaded into a host family where they would be aligned and locked to a Ref. Line that drives their angle with labeled dimensions.  Do you have a file you can post here? Be easier to show you than tell you.

[D.DI]

here is the model in revit 2019

[barthbradley]

I would have modeled this in a Family. At the very least, I would have modeled in as an in-place component. You need Ref Lines and parameters.  I would have also built the "skeleton" (with Ref. Lines) and made the skeleton fully parametric (e.g. made sure it flexed correctly) before aligning and locking nested model components to the Ref. Lines.  Similar to a Truss Family.  

...more to come

[ToanDN]

I would build the skeleton model as an adaptive generic family with  two divided paths.  That gives you a parametric top and bottom with all the points can be change in quantity and spacing easily.  Then draw the actual members / cables over the skeleton snapping to those points.