Families: Make two rotating reference planes, the rear dependent on the front

[Redrunner92]

I'm trying to make a family of a double-trailer semi-truck and I would like it to have parameters which allow both trailers to rotate, with the front trailer's rotation independent and rotating around the truck's hitch, and the rear trailer's rotation dependent on the front trailer's. When I tried to do this, the family consistently broke when I tried to flex the rear trailer's rotation parameter (which rotated the Reference Plane of the rear trailer's center line).

Has anyone created a family which successfully and consistently flexes in this way? I have attached an image which shows the two planes.

[Shaiki_]

Try the link below - it is not a short and sweet explanation, but a method to accomplish what you are looking for using revolves and reference lines is demonstrated in detail. 

https://www.youtube.com/watch?v=Em6n3J2L1UA

[ToanDN · Accepted solution]

You need to use Reference Lines, not Reference Planes.

[SteveKStafford]

FWIW double trailer also pivots more than your sketch allows. It starts at the steering wheels of the tractor, the first trailer connects/pivots at the king pin on the tractor, then at the dolly/hitch connection at the end of the first trailer and then at the king pin of the second trailer connected to the dolly's fifth wheel. Many such truck trailer combinations are "pup" (shorter) trailers for in-town while (tandems and in some states triples )  full length trailers (53 ft) are allowed over the road. As such, planning for a truck stop project can be quite different from in town truck delivery and warehouse conditions.

[Redrunner92]

That's good to know, thank you for the tip, Mr. Stafford.

[Redrunner92]

That took care of it, now the Reference Lines flex appropriately. I haven't modeled the geometry yet so I'm unsure how well the extrusions, sweeps and such will respond to the dependent rotation; however, that was not part of my original question so this is indeed a solution. Thank you, sir.

[Redrunner92]

I'd like to watch this, it looks like I may learn a thing or two from it. Maybe during a lunch hour (someday). Is the guy selling a product? If so I have no reason to watch it since I don't have the authority to purchase add-ins and the like.

[SteveKStafford]

Each solid/void needs to relate to the reference lines (hosted by them). The tractor forms need to be hosted by the tractor's reference line and the same for each trailer. You need to be careful to use Set (workplane) to make each active before creating your forms...or use Edit Workplane afterward to reassign them to the correct reference line. I think it is a bit more predictable if you start with the correct workplane active.

[Shaiki_]

Nope, it is just an Autodesk University class on dynamic families! Everything is OOTB Revit.