PDA

View Full Version : What is the best way to model floors, beams, collumns and floor finishes?



samov
2008-09-30, 06:02 PM
What is the best way to model floors, beams, collumns and floor finishes?

The question is a rather big one... The problem i have concerns all these elements when used together....

Q: On a "Level X" workplane you sketch the floor. Under this floor you model the girders and columns supporting it.

S1: If the floor has multiple layers some UNDER the main structure layer... joining it with a girder will CUT through the girder. There is another problem... the girder is set offset 0 from the level workplane and is the floor is quite thick you get a smaller "actual" girder from what you selected.
(this solution is the worst one and IT HAPPENS BY DEFAULT, and it's impossible to model multiple finishes on the same floor, without actually modeling multiple floors)

S2: If the floor has multiple layers and you model it as multiple independent stacked floors you end up with the walls on the next level attaching to the level and NOT the the floor above the level. You either attach all bases to the "last" floor (in this case the doors end up being lower) OR you start offsetting all girders to be lower (this seems simpler and less intrusive).
(well this is better, if you like your doors not being on the floor, alas it gives some good results as you can have a "structural floor" and multiple finishes floors on top"

Conlusion: I arrived at the conclusion that ALL floor layers MUST BE below or exactly end at the "Level X" workplane. The problem with the doors starting lower than the floor is just too annoying.
Conlusion 2: Well... it is obvious from an architects point of view... that there are actually TWO level systems in a building, one is the Structural, one the floor Finish layer...


So ... the software telling me that for each unique LEVEL, in a building, to get the 100% correct representation i need to either:

ONE
a. Have all girders set to offset UNDER the level workplane to take into account the floor finishes.
b. Have the floor NOT HAVE any layers below the main structural part... or else when joining with a girder it will cut through it with the finish layer.
c. Model multiple floors per LEVEL according to each regions finishes.

OR TWO:
a'. For each real LEVEL you should actually have TWO levels for ultimate control of the finish and structural layers.

IS THERE ANY OTHER WAY TO DO IT?

mthurnauer
2008-09-30, 08:46 PM
Just a quick point to make about the girders. Usually, the dimensions of a concrete beam or girder is measured to the top of structural slab.

cliff collins
2008-09-30, 08:50 PM
Good question, which has been raised before.

In our office, we have a "shell and core" revit file, and an "interiors" revit file, which we link to each other.

The structural floors are in the "shell/core" model

The finish floors (carpets, tiles, wood flooring, etc.) are in the "interior" model

It is true, that unless your door families have been modified to have an undercut to allow for finishes--that the door panel will be below the finish floor. In reality, the shop drawings/contractor allows for the finish. Revit is exposing a "real-world" issue with a virtual world model.

I DO NOT recommend using (2) Levels at each floor--one for structural floor and one for finish floor. This will cause unnecessary complexity.

Cheers.....

sbrown
2008-09-30, 09:01 PM
Your last answer is the "right" one. I make a workset for structural levels, ie, t.o steel, t.o slab, etc. These are on a workset that is off by default, then I can only see them when I want them.

samov
2008-09-30, 09:23 PM
Just a quick point to make about the girders. Usually, the dimensions of a concrete beam or girder is measured to the top of structural slab.

Yes. I agree. That is why adding floor finishes and not using offsets to account for that in your girder system produces weird results.


Good question, which has been raised before.

In our office, we have a "shell and core" revit file, and an "interiors" revit file, which we link to each other.

The structural floors are in the "shell/core" model

The finish floors (carpets, tiles, wood flooring, etc.) are in the "interior" model

It is true, that unless your door families have been modified to have an undercut to allow for finishes--that the door panel will be below the finish floor. In reality, the shop drawings/contractor allows for the finish. Revit is exposing a "real-world" issue with a virtual world model.

I DO NOT recommend using (2) Levels at each floor--one for structural floor and one for finish floor. This will cause unnecessary complexity.

Cheers.....

Thank you for pointing out this has been discussed before. I will search for the other threads.
The problem i described can lead to a lot of complex issues. Yes, i agree that anything less than 5 cm can be "fixed" but anything more than that and you have a big problem.


Your last answer is the "right" one. I make a workset for structural levels, ie, t.o steel, t.o slab, etc. These are on a workset that is off by default, then I can only see them when I want them.

Wow... Interesting workaround. I will test it myself and post the results.

--------------------------------------------------------------------------------------------------------------------------------



Thank you everyone. Thank you AUGI. This thread is not closed. Any other comments are welcome!

samov
2008-10-04, 05:07 PM
I have tried to find a solution to this rather unpleasant problem. It seems the workset technique is the best one, although it requires you to use worksets on a project that does not necessarily need them.

I have tried another approach, modeling the structure in a completely different revit file and linking the files.

I am however very curious how people using Revit Structure deal with the problem. For example if the Architect and Structural offices NEED different levels ... is this done using the above workset method?

d.stairmand
2008-10-04, 11:42 PM
In our Office We only have 1 Floor Level - the Structural One.
All of our floor finishes are On top of the Structure, being a 10-25mm floor of Carpet or tiles.
The Structural Engineers Prefer this - as they can then just copy or Structural Floors. If we have the Carpet, & Structure etc. in 1 Floor - they cannot copy the Elements.
Worst case senario happens - what is they don't even put the Carpet down? or even use one with a really thick backing - all you floor levels are then wrong!

Mike Sealander
2008-10-05, 12:42 PM
We use the structural floor as the object tied to the level. Finishes are built on top of the structural floor as separate floors.
Occasionally in residential projects we build the entire floor- structure and finish- as one object.
The question "What is a floor?" is not so much a philosophical one, but an operational one. What do you want to get out of floor objects? I think the answer is at least partly "good graphics and good schedules".