topic Re: Revit not calculating quantities correctly in Revit Architecture Forum

Revit not calculating quantities correctly

Prvoime — Wed, 18 Nov 2020 23:33:37 GMT

Revit, a BIM software, doesn't calculate quantities for material takeoff correctly. Test it. Create a brick wall 0.2×1×1 meter. Volume is 0.2 cubic meters.
Now slap a concrete column through it. Or two, or three. Revit still reports volume of that brick wall as 1 cubic meter.
To get the correct volume you have to join those elements. I'm sure you all know how many structural columns and beams are there, even in an average size building. A massive waste of time and so many opportunities to mess something up.
You may say just subtract one from the other. Nope. There can be a ton of those that are partially inside of walls and ceilings so that wouldn't work.
Revit really should be smart enough to know that two objects can't occupy the same space at the same time. Especially when those objects are a d*mn brick wall and a concrete column.

How do you deal with this?

Re: Revit not calculating quantities correctly

barthbradley — Thu, 19 Nov 2020 00:19:45 GMT

Post something here for us to test, not build from scratch- per your written specifications - and test. Help us to help you.

BTW: This is a USERS forum. Just thought I'd point that out in case you were unaware.

Re: Revit not calculating quantities correctly

JF.K — Thu, 19 Nov 2020 08:11:49 GMT

Revit calculates those values accurately, you just have to tell the software what you want it to calculate for you.

@Prvoime wrote:

To get the correct volume you have to join those elements. I'm sure you all know how many structural columns and beams are there, even in an average size building. A massive waste of time and so many

If the only way you found out is to do this operation manually, then yes it is indeed a waste of time and very likely you are going to miss selecting some elements. If the software doesn't work the way you expect it to work you should go deeper and give task automation a try.

You are trying to:

see if two different categories intersect (partially or not)
if they do, join them automatically (if they can be joined). If they don't, leave them as they are

What you are trying to accomplish is an example of a rather simple task for Dynamo for Revit https://forum.dynamobim.com/.

There are some topics about auto-join or joining different elements based on one or several conditions. Maybe this can help you out https://forum.dynamobim.com/t/auto-join-elements/12323

https://forum.dynamobim.com/search?q=join%20elements

Re: Revit not calculating quantities correctly

Prvoime — Thu, 19 Nov 2020 08:29:16 GMT

@barthbradley wrote:
Post something here for us to test

No problem, attached a simple example. If you look at the schedule I created, "Brick" is reported incorrectly, "Brick - joined" is reported correctly.

BTW: This is a USERS forum. Just thought I'd point that out in case you were unaware.

I know, that's why I asked how others deal with it, because I guessed it's something that can't be dealt with easily since there are possibly hundreds of columns and beams and doors and windows lintels that would need to be joined.

Other user suggested Dynamo, which is at the moment above my level of expertise.

Re: Revit not calculating quantities correctly

Prvoime — Thu, 19 Nov 2020 08:32:10 GMT

@JF.K wrote:
What you are trying to accomplish is an example of a rather simple task for Dynamo for Revit

If possible, that would be great! Haven't got to Dynamo in my Revit education yet, I'll make sure to check it out. Thanks!

Re: Revit not calculating quantities correctly

barthbradley — Thu, 19 Nov 2020 18:23:27 GMT

I'm not sure what issue you are pointing out or what Dynamo is suppose to do. From what I see, you have geometry embedded inside other geometry. To resolve this conflict we use the Join Geometry tool to substract the overlapping geometry. Switch Join Order tool changes which geometry gets removed in the union.

Re: Revit not calculating quantities correctly

Prvoime — Thu, 19 Nov 2020 18:39:28 GMT

@barthbradley wrote:
To resolve this conflict we use the Join Geometry tool

That is the problem! You shouldn't have to use that tool in situations like this, at all!

Like I said earlier, not a problem when you have one wall and two columns, but you can have literally hundreds of columns and beams and doors and windows lintels that would need to be joined. Modern BIM software should be smart enough to know if a concrete column goes through a brick wall - subtract column volume from brick wall. The way it does it now, it reports false quantities, plain and simple.

Re: Revit not calculating quantities correctly

barthbradley — Thu, 19 Nov 2020 23:06:48 GMT

@Prvoime wrote:

Modern BIM software should be smart enough to know if a concrete column goes through a brick wall - subtract column volume from brick wall.

What if it's a brick column and a concrete wall?

Re: Revit not calculating quantities correctly

Mohamed-Nassar — Fri, 20 Nov 2020 01:21:35 GMT

you are right Mr. @Prvoime Revit is not the smartest way at some features may joining one of them and who's working for different platforms will notice this fast because it's logical detected but here's not i recommend to learn more Dynamo and Visual programming it's very helpful tool with repetitive task for Revit and used for conceptual design also and the next generation of this tool is the Generative design i think it worth to teach about them.