Revit IFC Import

[Archiphreak]

Has anyone had experience importing IFC format files exported from Revit? I have a large project for a university and our firm is partnered with another firm for the architectural development. We'll also be sharing models with the contractor at some point as well.

Any help/guidance is always appreciated!

Thanks!

[gester]

archiphreak, don't bother reading negative statements. go for it.

i'm just test exchanging ifc files with my mep/hvac consultant (revit/revit mep) and the troubles are with some booleans and roof-trimmed walls (while importing the ifc into revit). otherwise the geometry works ok.

the project won't be big (12000 sq.ft.), but for clash detection even with those errors the ifc is enough.

will your models be merged or otherwise referenced, apart from the clash detection?

will you have sloped roofs trimming the walls? - there could be the flaws.

Edited September 13, 2013 by gester

[gester]

sbg

your deprecating statements don't impress me anymore. there was hardly a single issue here you were positive. i try to avoid such people.

believe me, i will work out _any_ obstacle.

[gester]

we intend to go the full ipd way, including the contractor and subs along the design process, and managed by an independent bim construction manager.

there will be no tender, but the target cost with target value design and the quality specifications. and with value engineering to control and to balance the overall cost and the one for each craft.

any significant doubt and ambiguity is supposed to be solved in the design charrettes. and we'll manage the minor ones as well.

[Robert Anderson]

Archiphreak and Gester:

I've been importing a number of files from Revit to Vectorworks lately. Here are a few tips:

• Make sure that your collaborator uses the latest version of Revit (2014). This is the version that delivers certified IFC files.
  
• You should use the latest version of Vectorworks (2014). This will optimize import file sizes by a bunch. File sizes will be 50% or less compared to Vectorworks 2013 and earlier.
  
• Be aware that Vectorworks imports wall and slab geometry (any geometry that has voids) as CSGs with histories. Right now, there are no built-in optimizations for this. Depending on the precise file makeup, this can make for very large imported files. I post a script below to make this better.

Remember that most Revit users are (just like you) focused on making a drawing set, not a nice, clean interoperable model. As a result of this, you'll find many "quirks" that have to do with day-to-day practice, e.g.:

• Walls that go more than one floor: Even though this is not, strictly speaking, the way that IFC likes the world to be, Revit often does things this way because of its data structure.
  
• Repeated elements that are not "symbolized". IFC does not strictly support a strictly instanced data-structure like a symbol. It does support a "type", which is a little looser data structure. Often times, if you have e.g. many instances furniture with a lot of curved or mesh geometry, these essentially come in as IFCentities, which are non-instanced PIOs. We will over time get better at this, but for the moment, you'll have to turn these into symbols and replace them yourself.

Now, as promised: a little script that will remove histories from all CSG objects in a file. I recommend that you start with an empty Vectorworks file, import the Revit file, and run this script (which should cut a significant proportion of the file size) before you begin doing any Vectorworks drawing or modeling.

{=====BEGIN VECTORSCRIPT=====}

PROCEDURE test;

FUNCTION Remove_Solid_History(h_obj:HANDLE):BOOLEAN;

VAR h:handle;

BEGIN

setobjectvariableboolean(h_obj,630,FALSE);

Remove_Solid_History := FALSE;

END;

BEGIN

ForEachObjectinLayer(Remove_Solid_History,0,2,1);

END;

RUN(test);

{======END VECTORSCRIPT======}

Best, and hope this helps, Robert

[Robert Anderson]

Chris, can you provide more detail about what you are trying to do? (There are some new planar criteria in VW_2014.)

[gester]

robert,

thanks for your insight and for the script. i must dwell upon a bit, especially if i still haven't upgraded yet.

rob