align with ref planes possible

[Cheuk Ling]

Inside the attached file, I have drawn a cranked beam.
I have set up all parameters to be instance in the beam family,
so it allows me to adjust the drop edge , cranked base by eye
or by correcting the instance parameters. But if I want to
align (say the drop edge) to a ref plane, revit doesn't allow me
to do so.
Any work around to make it possible ?

[erikbjur]

If you want the top drop to align with the bottom you need to delete the dimension linking the top and bottom reference planes. Other wise, I got them both to align with the ref plane. Once I aligned them to the Ref plane, I could only move the plane right. Moving left would cause an error.

[Cheuk Ling]

thanks Erik,

let me put my question more clearly.

I want to keep the top drop and bottom crank dimension unchanged.

Since beam is a two pick family, i.e. When I loaded this to my project,

I just need to define the two support points , however, the top drop

position maybe vary in different situation. Therefore I just want

to know besides parametric alternation, or by eyes , can I use something like

align ref plane if I know the exact location of drop.

best wishes