Force top of beam location

[AdamCP]

Hi folks,

Just wondering if it's possible to explicity set a reference plane/line as the top of a beam within its family, so that even if there's geometry above this point, Revit ignores it and uses the specific plane.

I have a fascia beam family which has a parameter to let you rotate the top flange to match varying roof pitches, but doing so pushes the beam up and down because the top of the geometry changes. I'd like to set the origin of rotation as a constant 'top of beam' point.

Cheers,
Adam.

[Thomas Maleski]

I'm not in front of a machine with Revit but I believe that the shape profile's centroid is at the origin. So if you want it always at the top, move the profile down. I would name the file different from the origin since it will behave differently than one would expect.

[Jshaver]

The way Revit handles the beam families from what I recal is that regardless of where your geometry is in respect to the origin the top most portion of your geometry is always considered the "top of beam". The workaround I used to control the location of the geometry was to create an "invisible" model line constrained to the geometry with an editable parameter. For example I used this to create geometry with a slab depth parameter to remove the concrete overlap prior to RS2009's autojoin feature. Simply constraining a parameter to the origin ref plane would not work.

[AdamCP]

Thanks for the replies, folks. The 'invisible model line' method should prevent the beam from translating when the geometry is flexed, but only if it's located above the highest point the geometry can attain. I'll just have to use a positive z-offset from plane to bring the beam up to the correct location.

Cheers,
Adam.

[Jshaver]

My appologies for providing a poor workaround.
The model line could be constrained a fixed distance past the geometry's highest point....but a better way to handle this would be to create a reference plane and set it's properties to define the "top" reference. This will allow you to place the element using that plane as the reference elevation regardless of your geometry's extents. I'm not sure why that procedure escaped me before.

Make sure when you place the element you are setting the z-justification to "top".

[AdamCP]

That was the first thing I tried, actually, as it seemed the most logical way to set what I wanted to be considered the top plane of the family. However, Revit still insists on using the high point of the geometry as the top, if it's above the plane.

Your original suggestion works fine, though, and the member isn't going to be used so much that giving the beam a z-offset to compensate would become a tedious task.

Cheers,
Adam.

[djc1984]

I'm trying to get the origin of my beam to be the 'top of bottom flange'. Basically I want to place the beams, by level, at the top of bottom flange, without having to put an offset z value from the top of beam. Any ideas??