Associating elbow nominal radius with pipe diameter

[h3khaira]

Hello, 

I was wondering if anyone knows a way to link the radius of an elbow to the diameter of its associated pipe. The reason I want to do this is to change the elbow size when the pipe size is changed. 

Right now if I change the size of pipes in a system, the elbow sizes remain static. 

Thanks!

[iainsavage]

Create two instance parameters from Piping category and type Pipe Size.

One will be for the pipe diameter (call it Pipe Diameter or whatever you want), the other will be for pipe radius.

Use a formula to relate these to each other e.g. Pipe Diameter=2*Pipe Radius.

Associate the connectors in the family to either the radius or diameter parameter depending on whether the family setting is Use Radius or Use Diameter.

For the parameter which drives the fitting radius also use a formula e.g. Elbow Radius = Pipe Radius or whatever names you are using. Depending on the types of parameter that you’ve used for the elbow radius you may need to add a correction to the formula to avoid the Inconsistent Units error by multiplying by 1mm or 1” etc.

[robert.klempau · Accepted solution]

Hello @h3khaira ,

In Revit MEP the Pipe has an inside and an outside diameter. Both are connected to the Nominal diameter parameter. In a Floorplan or 3D View, you see the Outside diameter of the Pipe.

Revit Families have connectors that are connected to the Pipes via their connectors. Pipe connectors are driven by the Nominal diameter of the Pipe not the Outside diameter of that Pipe.

Therefore Revit has Lookup Tables.

It depends on how old your family is but old Pipe fitting families have mostly the Nominal Radius connected to the Pipefitting connector. And that Parameter is used in the Lookup formulas to get the outside diameter from that Lookup table.

If you only change the Pipe size at one end of the Pipefitting and the Pipe size at the other side of the Pipefitting, Revit will only place a transition fitting between the Pipe and the Pipefitting.

When you select the pipe fitting and the Pipe when changing the Pipe size, both will update.

When you select a complete run and change the Pipe size, all the fittings will update.

The Pipefitting in the attachment works just fine. Please try this one. And let me know if this helps