RAM Structural System – ISM – Revit Structure Integration: The greatest thing since cassette tapes

Because I work for a technology company, it is with significant embarrasment that I admit I am not an early adopter.  For quite some time I refused to see the value in texting.  “I have my phone in my hand.  You have your phone in yours.  Why not just call each other?”  Try as they might, my friends could not convince me to join Facebook.  I scoffed at needing an iPad in addition to a laptop.

It is a mentality that I also see regularly with RAM Structural System users, who for years have relied on Bentley’s direct link between RSS and Revit Structure to exchange information in a BIM format.  They don’t want to embrace the newfangledness of ISM:  the Integrated Structural Model.

But, just look at me now.  Texting more than talking.  Keeping up with friends and family via Mr. Zuckerburg.  Watching an actress on TV while researching her on IMDB with my tablet.  And, of course, blogging!

Grudgingly, I have come to realize that the old ways are not always the best ways.  While cassette tapes can still play music just fine, CD’s and MP3’s offer so much more.  Similarly, although the direct link still works, the ISM transfer increases the integration capabilities present between RSS and Revit.  To encourage you to experience the music of integration more clearly, I offer here some ISM Integration Tips and Tricks.

A:  RSS to ISM to Revit Workflow

A1.  When possible, start your model in RAM Structural System.

  • RSS’s more stringent modeling tolerances provide a smoother initial exchange with Revit.  In addition, levels and their plan views are automatically generated in Revit this way.

A2.  Be careful with polygons.

  • When defining decks and loading, do not use the overlay feature in RSS.  Draw individual, non-overlapping polygons.  Revit will use only the initial polygon and ignore superimposed polygons.

A3.  Know the transfer limitations. These items do not yet transfer into Revit (as of ISM v3.0):

  • Rebar
  • Base plates and connections
  • T-beams and pan joists
  • Mat foundations
  • Coordinate offsets and column splice offsets
  • Castellated / cellular beams

A4.  Use the “Match All” feature during the mapping process.

  • This maps all Revit families, even those not in your project. 

 

B:  Revit to ISM to RSS Workflow

B1.  Don’t worry about analytical lines.

  • ISM uses the physical Revit model for integration.  Therefore, model all physical members to the appropriate support point – usually the centerline.

B2.  Specify lateral / gravity members.

  • Before or after drawing the member, set the type in the “Properties” -> “Analytical” (dropdown) -> “Analyze As” dialog box.

B3.  Be aware of levels and offsets.

  • Any item expected to exist at a specific floor in RSS must be modeled to a specific level in Revit.  Offsets from the level may be used for sloping members.

B4.  Model in plan view.

  • Create plans at distinct levels and use grids for primary framing.  This ensures that most members are set to the correct equivalent RSS floor.

B5.  Expect to make some modifications in RAM Structural System.

  • Slabs often come in to RSS as two-way.  This can be changed to the proper one-way distribution after import.
  • Turn on the grids at each floor.  The grids import but are not automatically visible.
  • Beams with cantilevers may be supported at the end of the cantilever, requiring re-framing.
  • Braces may not attach at both levels, requiring re-framing.
  • Revit often merges two walls at a corner.  Use the “Integrity” -> “Align” -> “Walls” command in RSS to adjust the endpoints to centerline.


B6.  Use the Structural Synchronizer tools.

  • Filter by New / Deleted / Modified
  • Selectively Accept and Reject changes


 

I encourage you to give ISM a try using these tips and tricks.  Metaphorically wind your last cassette with a pencil eraser!

To get started with ISM today, download the FREE Structural Synchronizer and Revit ISM Plug-in from www.bentley.com/ism