Ram Structural System versus Risa for analysis in conjunction with Revit Structural

[kbradway]

Our company is primarily a structural engineering firm and is currently investigating the use of Revit for certain projects. We use both Risa-3D and occasionally Ram Structural System for larger projects to aid our designs. We are looking for feedback on Revit projects that have worked well with Risa-3D, Ram Structural System or both as the structural design package used in conjunction with Revit Structural.

What types of projects (anywhere from one level small platforms to entire buildings - composite, steel, concrete systems) work best for Ram Structural System or Risa-3D in conjunction with Revit Structural?

What major pros and cons are there to using Ram Structural System versus Risa-3D in conjunction with Revit?

Can both programs be linked to the 2010 version of Revit Structural?

Any other information regarding the use of one program over the other would be helpful.

Thanks,

[david_peterson]

Well the nice part about risa is that it's a node based program and Ram isn't. Revit also works off of nodes (points in 3d space). However if you want to do composite floors, you will need Risa floor as well.
Ram has usually been a little more ahead of the curve and more than willing to help fix any problems or errors that you may come into.
Risa was about 1 version behind with their link the last time I looked.
I'm not sure about Risa as we've never really tried to take a project back and forth with Risa. We've done so with Ram, but we only did it as a one shot deal. Bentley was in the process of creating the first real porter for Revit. In theory you were going to be able to take a Ram model run it though the porter to Ram 3d back to ram to Revit to Risa, back to revit, back to ram and so on........ But I'm not sure where they are with that development.
My point is that Engineers don't model @ 1/256" but they will have to if you want your model to come out correct. Also you'll need to do everything in Inches and not Decimal Feet. For some reason I want to say the Ram only take Geometry point down to 4 decimals where Revit goes 14 so rounding errors can also come into play.
Here's the reason why I don't think the link works real well. They produced a little tutorial with the release of R4. They still use the same building in all of the presentation I've seen from Ram, and still have to make the "Oh, I don't know what that happened, here I'll just hit the undo button and try again." If you still get errors after using the same models for 3 or 4 yrs, you might not have the best thing since individually wrapped sliced cheese.
But that's just my opinion. Oh I should also mention the last project we tried this on (4 story building about 200k gross sf,) and it took a little more than 8hrs or grinding to get a almost working revit model exported from Ram.

[kbradway]

Oh I should also mention the last project we tried this on (4 story building about 200k gross sf,) and it took a little more than 8hrs or grinding to get a almost working revit model exported from Ram.

Thanks for the input, David. The 4 story building that you mentioned above - Did you start your model in Ram and then export to Revit (or vice versa)? Most threads I have come across indicate that one should start in Revit and export to structural software to save heartache. What are your thoughts?

Thanks,
Kevin

[david_peterson]

We originally did the building in Acad and the contractor requested a 3d model and the owner said they'd pay for it so we exported the Ram model "AS IS" and that didn't work. Our engineer went into his ram model and switched from feet to inches, adjusted his model to fix the rounding errors and exported to Revit. 8hrs later we had most of a model. We still needed to add gusset plates to brace frames and channel frames and angle frames for openings. So there was still a fair amount of work that needed to be done.
If you are going to try this, read ALL of the material that Ram puts out (Or Risa) about the link and the how toos. Just like many things in revit, you have to do things a certain way in a certain order to get it to work correctly.
If you start a model in Revit, you can take it to either Ram or Risa, but when you do, you're going to get errors like unsupported ends, and braces may or may not connect to the correct node.......You have to not only be paying attention to the physical model but you'll also spend time adjusting the stick model inside of Revit.
You can take a revit model to Ram, Risa 3d (and then Risa Floor, back to 3d back to Revit), E-tabs and I think Safe.
Starting in Revit would be a better idea, however my engineers don't trust it, and for the most part only want the grids. From what they've told me the few times we tried these kind of things, they spend more time fixing the model than what it takes for them to just create one. They do love the grids though.

[RISA Matt]

I cannot speak for the RAM-Revit link, but I would like to clarify some points about the RISA link. We (RISA) are an Autodesk Premier Partner, which means that we have access to alpha versions of Revit and its API long before anyone else. We have had a Revit 2010 link (for both 32 and 64 bit versions) available since June 2009, and we plan to have a 2011 link out before that date this year. In fact, we have already started working on our Revit 2011 link.

RISAFloor is a building design program which fully integrates with RISA-3D. It does composite steel design, optimization for deflection, steel vibration checks, flexible diaphragms, and a whole host of other features. Our RISAFloor-Revit link is definitely more advanced than the RISA-3D-Revit link, however both are very robust and reliable.

Our link features a built-in tolerance for points, so if there is a minor decimal difference between your RISA model and your Revit model we will automatically correct it. The link also works equally well going from RISA to Revit, or from Revit to RISA.

You can find many details on our link from our website here, including a Demo Movie that shows how our link works.



If you attended Autodesk University but did not attend my class on the RISA-Revit link, it is available streaming from the AU website:



Anyway, that's just my two cents, but I'd be glad to answer any questions that you have.