Bridge Crane Help?

[Kirk Bricker]

I am having some parameter problems with a simple bridge crane family. It seems the structural W-shapes don't like to be locked to ref planes, and they do not flex? I would like to be able to change the runway beam size, and the girder size.
Eventually I would like to have two bridge crane families: one that is supported by the roof structure, and one other that is supported by columns equally spaced.

First task: When the span is increased the girder length and offset does not stay, and the RW (runway beam) height can not be adjusted without Revit screaming at me.

Any help?

Thanks
Kirk

DesignBuild Solutions
a division of Neumann Brothers, Inc.
Des Moines, Iowa

[Paul Andersen]

Kirk,

I took a stab at your bridge crane family and came up with a couple of solutions and a possible work around. With regards to adjusting the height of the girder and runway beams you were almost there. I added a reference plane for the bottom of the runway beams and set the appropriate reference planes as the framing members working planes. I then changed the vertical justification of the runway beams to bottom. Once the reference planes are set as work planes for the members you can establish any relationships you would like by the usual methods.

Having not attempted to lengthen a nested structural framing member before I was under the same assumption as you that locking the ends of the member to reference planes should do the trick. Unless I am missing something obvious, which has been known to happen more often than I care to admit, this does not seem to work. Here's where the work around comes in. The girder could be generated from scratch as either an extrusion or sweep. While this does require a bit more effort intially and changing the member's size is not as straight forward I have utilized this method on several occasions where curved or sloped members have been involved or for built up sections such as plate girders with great success.