Concrete Beam Material Take Off Surface Area Schedule - Problem

[G_J]

This is a post I have been meaning to put up since the back end of last year, for some reason I put it on the back burner and then never came round to writing it up.

I was asked if Revit can schedule the surface area of concrete beams for the purpose of calculating how much paint would be required to cover the beams.

My simple response was of course Revit can do that....

So I quickly got to work and soon realised something wasn't quite right, when doing a test manually to calculate the surface area of the beams in a small portion of this model, the answer I was getting contradicted the schedule within Revit.

Back to the drawing board.

I soon worked out that the problem is when a beam was joining a wall or column. The 'surface' that joins that wall or column, in theory should not show up in the surface area schedule, because that face will not be painted, that surface will never be visible due to the nature of concrete construction - concrete 'joins' concrete.

Revit however doesn't recognise that (even though Revit does recognize that concrete joins concrete)

In other words, what use is a material take off surface area schedule within a project that does not provide the actual physical / visible / constructed surface area?

The surface area Revit is showing in the schedule will never be visible, in theory the surface area of a concrete beam tied / cast against a concrete wall does not even exist, it may even be cast with the top of the wall depending on the construction sequence of the structure.

There are images relating to this and a little more information on my blog post

http://revitst.blogspot.com/2011/02/...face-area.html

[david_peterson]

The interesting thing is that it works correctly for volumes. Revit will take beam joins into account with volume as well as beam/slab join/void. I have a feeling this is because revit wasn't set up for surface areas of joined/cut elements. Just my thought.

[dhurtubise]

Still wouldnt stop me. How about sitting with the estimator and getting a factor in?

[Craig_L]

I don't believe that Revit is not handling this problem properly.
I think the problem is that (for revit) the question is too vague.
By that I mean - its not specific enough. Revit is actually returning to you the exact values you have requested of it. For some items this would be useful, steel for example, will be entirely painted, where-as for beams joining into walls, this is less accurate as it doesnt consider the meld of the two and subtract the appropriate number from the total.
But as for walls, if you apply sheeting, does it consider painting both sides of the sheeting instead of just the exposed surface? I would say no, it gives you the surface area total, which is exactly the question you have asked of it.

I imagine that some kind of formula could be derived to bring these values closer to the desired result, or you could work with a different program to export your model and calculate elsewhere...

I understand your issue, but Revit is giving you the exact result you have requested of it.