Revit - RAM link question #2

[khanson-3b]

Has anybody had any luck linking your model into RAM? I have tried it a few times and I end up w/ about 2 pages of error's and my ram model is broken up (walls split in half, footings distorted and my sloped joist's dont show up). I dont know if this is something I am doing or if this link just isn't there yet.

Please help shed some light.

Thanks

[david_peterson]

The ram link if kind of fussy. What type of errors are you getting. When you model in revit, one thing to remember is that ram has some limits when it comes to Revit. Revit is a node based model and ram is more of a floor based model. Most will tell you that the Risa link tends to be a little better.

So for starters, you can't have a col that spans multiple levels. 1 col per level per grid intersection required. Next, Ram can't do multiple diaphragms on a single floor. ie you can't have roof deck and Comp slab on the same level. If you don't put on a deck or slab in Revit, and span cols only one level, that should get rid of most of the layers. Also if you are using custom families, make sure that the mapping file is looking at the correct families. Just some thoughts.

ps, if A mod happens to see this can you please move to the revit Structure-general forum.
Thanks

[Tom Weir]

Hi,
Columns can't span more than one level, that's not so good. I think just last week we were discussing how we want to model structures in the way they are built, thus I usually have my columns going about two levels plus splice.
So does that mean that if I have developed my model I have to go and split them, or can the RAM model be adjusted.

I am also getting a lot of error messsages that makes me nervous.
Also my braced frames are still having problems. See the attached photo. All looks fine in Revit but in RAM the frame members are not meeting at the node points. I have the horizontal beams with an analytical plane at the center, and labeled as horizontal bracing.

Any Ideas?

Tom Weir

[david_peterson]

Do you have your anaylitical plane set to the same Elevation (Ram dosen't do slopes). Just a thought. Currently you can't get Ram to "Splice" the cols at from the Levels pull down. I'm not sure why it dosen't work. We've got that question posted to Ram. I'll let you know the response. Keep in mind that it you do splice cols at every level, it's going to create hovoc on your Col schedule. I sent a model to Ram yesterday and recieved 457 errors and 60+ warnings. After the cols were replaced in Ram, we were down to 8 errors.

[Tom Weir]

David,
<anaylitical plane set to the same Elevation>
Not sure what you mean by that. I changed the sloping roof member's analytical line to the roof so they are all flat.

How do you find the people at RAM? Are they working hard to help us or are they luke warm to this? Now that Bentley owns RAM I am wondering how robustly they really intend to support Revit Structure. When I export my project to ETABS everything looks fine and I get no error messages, so I am wondering just what is going on here.

I have been trying to promote the analytical model and how we could use it to our advantage in our company, but these results are almost an embarresment to me.

Tom

[david_peterson]

It was the slopping member that I was questioning. Ram has be just as good as Adesk if you ask me (When it comes to trying help us out). When we run into issues, we can send them the model along with error log and they take a look at it and usually get back with in a day or so. The responses are similar to those we get from Adesk on questions. Either Yep, we know there's a problem and we are working to correct it, so in the mean time, here's the best fix; or Ram can't do that, so you have to do it in a way in which Ram can understand it. They have made a lot of improvements to the link. You don't have to re-introduce your loads anymore. ie when you export to Ram, set up your load cases, send back to revit. You can export back to the same Ram file now which starts to make this link more usable. They seem to come out with new links about every 3 mths it seems. While they are owned by Bently, I think the Ram division is still kind of under it's own power (Sim to the Revit Group at Adesk right after they got bought out).

One thing to remember is the big basic difference in the way the Ram runs and the way the Risa and E-tabs runs. Risa and e-tabs are Node based, Ram is more "Floor" based. Ram also takes a few assumptions when running the model that Risa and E-tabs don't.
Anyway, that's my 2 or maybe even 4 cents.

[Tom Weir]

Thanks a lot David for your responses. It seems you have really been trying to use the link as best as possible. I'll just have to stick with it.

Can you tell me how and who you contact at RAM with technical problems.

Tom

[david_peterson]

I sat here yesterday trying to get my model to kick out to Ram. I had my dept. head, 2 other engineers, 2 designers and 1 other Cad tech all trying to figure it out. Our Dept head wasn't to optimistic about the results. It did help our designer out by getting the grid and most of the beam layout into Ram. He just had to spend a day fixing the issues. We got on the beta test for the link. It's come a long way since then. Then again so has Risa's link. We've only got one guy in our office that knows how to use E-tabs and about 3 that can use Risa in a productive manner. We are mostly a Ram Firm. We spent time looking at Ram Cad Studio. If you haven't played with that yet, you may want to check it out. It's a slick little program. (Dosen't work with Revit thought, Only Acad)

[Tom Weir]

We don't do a lot of RAM analysis but indications are we would like to, especially if we get this link with Revit working. We use ETABS and our own in-house version of TABS.

But your point about node versus floor based architecture make me wonder....
I guess I have to inform the engineers now of the limited nature of using RAM, at least for now.
In general the analysis companies don't seem yet to be flocking to make integration links with Revit Structure.

Tom

[david_peterson]

From the little bit that I know, Ram is a more effecient program and tends to be eaiser to model in and apply loadings in, but won't do slopes, won't do expansion joints in Floors, won't do alot of the things that Risa and Tabs can do. Risa tends to be harder to model in, but dosen't care about Expansion joints, or sloping members or anything. You can do anything you want in Risa. Here's another limitation of Ram. You can't do multiple diaphrams on one level. So you have to cheat at expansion joints or if you have say 3 pent house roofs on the same building. Risa you can. I believe that in Risa you can also use multi-story cols, but don't quote me on that. Most of what I'm saying here is second hand knowledge from what my engineers tell me, so You may have to test this out on your own. E-tabs should function about the same as Risa, but with the addition of Risa floor you can now do composite slabs, which was the one thing that Ram did that no one else did real effectively. I hope this makes some sense.

[david_peterson]

We don't do a lot of RAM analysis but indications are we would like to, especially if we get this link with Revit working. We use ETABS and our own in-house version of TABS.

But your point about node versus floor based architecture make me wonder....
I guess I have to inform the engineers now of the limited nature of using RAM, at least for now.
In general the analysis companies don't seem yet to be flocking to make integration links with Revit Structure.

TomTom, one other thing to look at before you send your model to Ram (I forgot about this one) Make sure your brace cols properties are set to "Anaylize as" "Lateral".
I haven't done this in a while (as mentioned before) but I noticed that was an option before.
I think you may need to do the same for the horizontal member as well.
Good Luck.:beer:

[Scott Hammond]

That is correct. In RAM SS, all members that are part of a braced frame or moment resisting frame can have their "lateral" parameter set in Revit Structure prior to exporting. this way the elements will be recognized in RAM Frame.

[Tom Weir]

Hi all,
Well, we have been working with our Revit model export to RAM for about a week now trying to discover the kinks and the advantages, and I wanted to post a few remarks.

1. First, the RAM developers noticed our thread here and contacted me, and they have been very, very responsive to our queries.

2. As David has said the multi-story column issue occurred, so the columns would not export. So I copied the columns and made that copy one story, and that exported. Not great but it got the columns in there. Lack of multi-story walls and columns I see as a major issue for RAM to handle, because I will not (at least don't want to) model one story columns. Indications are that they are working on it.

3. Another issue that came up was that the RAM model tried to write back a brace member size of HSS8X8X1/2. But the Revit family reads as HSS8X8X.500 so nothing was updated and we got an error message.

4. The engineer doing the analysis found many problems with analytical member lines. So she erased and re-drew them in RAM. Mistake! If the beams were deleted and readded in the RAM model, the sizes will not get sent back since the new beam is not associated with the Revit beam.
But the engineers are very hesitant to work in Revit, in my office so far. I think the culture of CAD vs. Engineering software is at work here. That is sowly breaking down though.

5. I should have been more attentive to some of these items as I was creating the model. I finally realized the help button opened a PDF user guide. I thought I would attach that here for those who are interested. Check it out before exporting to RAM. (I gues I must have been in that macho...."I don't need no stinking user guide"....mode.)

Final thoughts: Nothing comes easily...the integration link idea still has merit, but needs a lot more development to become truly useful in the design process.

Have a great day....

Tom

[david_peterson]

Thanks for the points Tom. Currently I've been exported to Ram, just so my engineer can get the grids. Unforturnatly, that's about the limits of the my use of the link. When I did send it Ram yesterday, My HSS columns came in as WF cols anyway, so those had to be deleted anyway. I also see the benefit of the Link, I just want it to work better. I know we are just starting learn how to stand up and about to try and take our first baby steps. Heck, the programs only a little over a year old. I've also found Ram to be very open to suggestions and they are always looking for feedback. I've got one engineer that talks with them on about a daily basis. As time progresses, I think you will see vast imporvements on both sides. I think that Adesk needs to cut loose the locks on their API and allow everyone to see what's inside. The more these guys work together the better. Just my 2 cents.

[dyroff]

Hey all,

I'm pretty new to the forums, and thought this would be an appropriate time to enter the discussions.

I am an engineer with an architectural background and I am helping to bring our firm into the world of Revit. I am excited about it but I am also experiencing the same hesitation from the senior engineers (as mentioned above).

One issue I have run into is the modeling of cantilevers. In Revit, I am modeling them as two members, but this is not the way RAM creates a cantilever. Is there a way in Revit where I can manipulate the analytical line of one member to extend all the way to the end of the cantilever, and then turn 'off' the analytical line of the cantilevered section?

Thanks in advance.

--Chris

[david_peterson]

The short answer is yes. There are several other threads here (http://forums.augi.com/search.php?searchid=573870) that deal with that topic.

[Steve Mintz]

The short answer is yes. There are several other threads here (http://forums.augi.com/search.php?searchid=572695) that deal with that topic.
David - I can't seem to get your link to work. Have I just not had enough coffee yet?

[david_peterson]

David - I can't seem to get your link to work. Have I just not had enough coffee yet?Nope, its not you. I fixed the link so it should work fine.
I just used the "search this forum" tool for analytical (http://forums.augi.com/search.php?searchid=573870) lines and found these other threads. I haven't tried this yet, but you may see more funcationality with RS4 and the new ram link that is due to be out shortly, if it hasn't already been made available.

[djn]

Has anyone tried bring the model from RAM back into Revit? I read that with Revit 4 you should be able to do this.

[david_peterson]

I haven't tried that yet, but you could do it in 3 as well. You just have to make sure that your model is created (In RS) the way the Ram wants you to create it. Read through the RS lit that you can get from Ram's Web Site. Also, I've been hearing some very wonderful things that Ram sees for the next release. It's only taken about 2 yrs, but I think you will be very surprised at what will be available in future versions of the Ram Link.

[Tom Weir]

David,
Can you tell us any more about those feature capabilites, and when we might see them?

Tom

[david_peterson]

Well I'm not sure if it's public record or not which is why I'm a little hesitent to talk about it. But you may see the next release sometime around Q1 2007, or at least that's what I've heard.