topic Revit family geometry problems and stretch in Revit MEP Forum

Revit family geometry problems and stretch

Anonymous — Sat, 27 Apr 2019 16:05:14 GMT

Hello all,

I am trying to build a peculiar element for some(most) of you called seismic bracing.

This is to go into 3d coordination madel and the brace goes off from the utility hangers at a 45 degree angle.

My problem is two fold (currently)

Issue 1 - My reference line representing the brace angle stretches perfectly in my family and the sweep I have for the conduit brace arm also sweeps. I need it to stay at 45 degrees and it does it in the family. However, when I load it into a project when I "stretch" the dang thing goes flat or vertical and wont stay at 45 degrees!

Issue 2 - The top bracket that will attach to the deck needs to move with the top of the conduit sweep. I cannot for the life of me figure out how to do so.

Re: Revit family geometry problems and stretch

L.Maas — Sat, 27 Apr 2019 18:53:34 GMT

A quick example of my approach (not fully tested)

I made the "rod" as a nested family (workplane based) with a length parameter

In the host family I placed this on the reference line.

I used some goniometric fomulas to calculate the Height and Width based on length and angle.

Length parameter from the rod i patched through to the host.

You can find the family in attached project. You wil have to clean up the family. Might be better to create the brackets and rod ends asnested families.

Re: Revit family geometry problems and stretch

Anonymous — Sat, 27 Apr 2019 19:01:20 GMT

Hmm, I don't quite see what you did.

One item though that my original family had that I need is the work reference line linked to the plane for the "stretch"

reason for it is in 3d view the grips show up so I can stretch the arm for coordination and get to the deck.

The next hurdle I have after this is rotating the angle of the brace off 45 degrees to clear obstructions in the construction space but I am trying to walk before I run....

Re: Revit family geometry problems and stretch

L.Maas — Sun, 28 Apr 2019 05:47:55 GMT

You can have it with stretch points.

I modified the formulas. In this case the drivers are height and angle. When you move the stretch points the height of the unit is calculated. With the height and the angle known the width and the length of the rod can be calculated by goniometric formulas.

As mentioned the rod element is a workplane based nested family. In this nested family the lenght of the rod can be set. In the host family this rod family is placed and the reference line is used as workplane so that it rotates in the same manner as the reference plan. The formulas in the host family calculate the needed lenth of the rod (paramter length is patched to the nested rod family), so that it stretches to the other hinge point.

Personally I would not use the stretch points but us a height instance parameter to set the needed height.