Beam Extensions...

[aaronrumple]

Anyone figure out the whole End Extension Calculation and Start Extension Calculation in the factory beams? Structural objects get more and more obtuse with each release. Even Autodesks support site says - don't try to make your own - just use ours....

[lev.lipkin]

When beams are joined Revit shortens beams to fit to the shape of the supporting column or beam. If this default shape of the beam is not satisfactory, use extension parameter to get joined beam to desired shape.

[Graham Briggs]

Hi Lev,

I use this feature with good results in 3D views or plans at greater-than-course detail level.

But, the Analytical Projection line of beams still stops at the column/wall/beam nearest to the intended end. In wood-framing, many times it is necessary to extend the beam for drag, or shear-transfer, or to catch a couple more joists, but Revit doesn't show that properly in plans. I find myself having to draft in the "symbolic" beam-end extensions. This is very annoying and, IMO, very un-Revit.

Any thoughts?

Graham

[aaronrumple]

When beams are joined Revit shortens beams to fit to the shape of the supporting column or beam. If this default shape of the beam is not satisfactory, use extension parameter to get joined beam to desired shape.Ya. I know that part. What I'm curious about is the obtuse way the current families are put together. The W family has severl unnamed ref. planes and the extension parameter is being controled in some goofy way. Seems the template should have the same goofy stuff if that is what is required to make things work. (And it is more of a pain when you have to adjust a framing system...)

[lev.lipkin]

To extend beams use round control, not triangle controls. Triangle controls only adjust beam geometry at the join. The analytical line has nothing to do with those triangle shape handles, it is controlled by round control.

Family are built to provide those triangle controls and parameters using what is available in Family Editor (no special coding). That is why there are additional ref planes.

At some point I hope we will correct that one way (enhancing family editor to make such thing 'less obtuse') or another (using special function similar to Coping from Revit Structure). One limitation I remember was the fact that geometry driven parameters could not be negative, and shape controls provide both positive and negative adjustments.

[Justin Marchiel]

i just posted a question about attachment. it would be good to disallow joins for beams. maybe this would allow greater flexiblilty in controlling the end extensions?

Justin

[aaronrumple]

At some point I hope we will correct that one way (enhancing family editor to make such thing 'less obtuse') or another (using special function similar to Coping from Revit Structure). One limitation I remember was the fact that geometry driven parameters could not be negative, and shape controls provide both positive and negative adjustments.
It should be like the sill parmeter in the window door families. I shouldn't to think about the offset while I'm making the basic shape. And the end offset should just show up when I load the family. And of course it would use the join/disallow join like the walls.

...and negative lengths <and angles> should be allowed. Many times I could have used that.

I'll stop before I get started on joining geometry and cutting beams....

[dbaldacchino]

Well thanks to this post I figured out how to solve a little nagging problem when I needed to split beams and they showed up with a gap in between (existing beams to be shortened due to new construction....beams are both set to Existing but one split piece is to be demo'd in New Construction. In the existing model, I don't want to see a gap).

Just an observation....those triangular grips are really hard to manipulate. And why do they just show in plan and not in, say, a 3d view? They also don't snap, which make them less useful. One last thing...it would be a great enhancement if there was some visual cue to tell the user which side of the beam is the start and which is the end, instead of trial and error.

[Rhythmick]

it would be a great enhancement if there was some visual cue to tell the user which side of the beam is the start and which is the end, instead of trial and error. YES!!! the trial & error adds an element of stress that just isn't healthy!

[barathd]

Mike:

That is a very polite way of putting it. S T R E S S ??? Lev - please walk a mile in our shoes.

Regards

Dick Barath

[Rhythmick]

It would be real slick if the individual end condition (level offset, extension, beam pocket, release) could be accessed with it's own properties box with a right click on the dot without having to go into the beam properties box, scroll around searching for the proper parameter, guess which end your on, then back out of the properties box. Or if accessing the properties box through a dot right click, have it highlight the proper end condition parameters of the end dot you entered through (start or end).

[mrice.47661]

This was a circa 2006 post - but I'm having a similar problem now with concrete beams in Revit 2009. The concrete beams OOTB don't appear to have the separate triangular extension grips that the steel beams do.

Has anyone found a way around this while using concrete beams? I have a fairly large existing concrete column with a wide capital, and not having the beam have its ends extended into the main column geometry will leave a gap of about 3'-0" or so!!!! Not so good structurally.

[mrice.47661]

Ok - so I answered my own question.

For some reason, the PRECAST concrete beams behave properly with extension grips, but the cast in place concrete beams do not. As long as you're not too picky on the structural side of things, you can simply rename the precast concrete beam families and be on your way.

[dbaldacchino]

Haven't had a chance to take a look, but my bet would be that if you edit the families, you'll find that the geometry is locked to the wrong ref. planes (as Aaron puts it, quite obtuse!).

[swalton240189]

Why when a beam slopes or has a Z- offset do I lose the triangle controls?