Largest project acchived in BIM.

[Anonymous]

Hello everyone. AC, Revit, VW, AP users. I work in construction company. Right now we came across big (1.2 mil sqft) hospital project, and together with architects looking for best BIM software that will be able to run this project. Right now we are testing Revit (mostly because of architect) but when project goes into 250 kilo sqft hardware starts to say NONO (experience from other projects). It's a big problem. Hardware is not the problem (state of the art for today standards). Any experiences in that area?

[Anonymous]

Miki wrote:
Asking this question I was hoping to get answer like:

-We did 500.000 sqft residential project with no problem both on plan and in 3D window.

or (on the other hand):

-We did 300.000 sqft hospital and we had no problems on plan, but section were generated slow, and 3D was total disaster.

Anyway. Maybe some with that kind of answer now?

Once I have the same problem. I work on a 300.000 m2 site plan. Which has 700 villas(object) and some other buildings. The main problem is in 3d and sections. (not enough memory massage). We have 4 gig rem. 512 mg graphic card.
It depends on the how datailed your project. But the poly count add-on helps me to find the limits . With the own made objects(my site plan) the limit in 3d is 2,600,000 poligons. With archicad objects (tested in empty file) the limit is 5,000,000 poligons.

What we did ,
In wire frame mode I save the project in ATL format, cause atlantis can handle more than ac in 3D.
I take the sections part by part and add them. (take time but works)
no problem in 2 D.

[Anonymous]

My 2¢...

I have worked on a wide range of projects in ArchiCAD and haven't seen one yet that is too complex to manage by one means or another. There are many ways to handle complexity depending on the specifics of the project.

I imagine this is also true of Revit but I haven't had enough experience with it yet to know what the strategies are. I have gotten the impression that it requires some serious expertise to avoid performance problems on large projects, but the same can be said for ArchiCAD. Which program is better suited may simply depend in which one you have the better expertise available.

[Anonymous]

Ok here we go. I'm really aware how to handle and manage project LOD. I have been doing that for years. The thing is I have never encounter myself full complex (hospital I consider is pretty complex) 1.2 mil sqft project. Complexity of that project will be based not by someone putting 1000 of detailed trees, but by huge amount of really necessary informations (MAP for example). I think good computer can handle it but ... what do I know? I never worked on that big project. Somebody did? Any impressions?
Right now the software of choice is Revit but we already encountered several problems. Unlike in AC in Revit when you create 3D view you see everything in it on the getgo. You can't preselect what do you want to see now. You can crop (not a Crop command in Revit) your view range but it is hell complicated and in a complex building time consuming. That's why I asked users of all BAM packages.

Thank you for all replies.

[Rakela Raul]

funny but, the VA (Veteran Administration Hospital) is designing a large Hospital and the architects are also using Revit
(maybe cuz Revit has a MEP solution)

[Anonymous]

Revit uses many of the strategies AC does to handle large projects, though you can "modularize by file" better in AC than in Revit, though that continues to change with every release, so I suspect they're using the idea of better cross-linking of models as development continues.

I have not seen comparable large models in Revit and AC at once to compare them -- but that would be illuminating.

Revit's performance is not hurt so much by numbers of objects as much as numbers of relationships. Those relationships (between adjacent connected walls) make Revit convenient and also processor hungry on large projects. You can disable wall joins and do things manually which helps performance a lot. For example: we have a roof over a project that is all one object. And walls connect up from underneath. It's not a large project -- 70mb -- and other projects over 200Mb perform better. We would have been smart to break the roof up into several objects. And we could, if we didn't have anything else to do.

Much has been made of SOM's use of Revit on the Freedom Tower in NYC. There are other projects of similar polygon counts (if you will) being done in Revit, and they'll all tell you: Revit needs work in this area. And they're working on it right now. The next release of Revit is rumoured to address this problem.

Having all your eggs in one basket is fine: just watch that basket 😉

[Anonymous]

It is my suspicion (but only suspicion) that it is based on Autodesk pushing old ADT users to use Revit. Constructor have MEP as well. And Constructor 2007 will have much more. Unfortunately GS is not putting enough effort to propose them AC or Constructor as an alternative. Especially that AC is so much easier to use for old ADT users than Revit. They should make presentations by comparison ADT-REVIT-ARCHICAD.

[Anonymous]

Autodesk is only pushing ADT users to Revit only if they want to do real BIM. Autodesk knows ADT's complexity means people use it like people use Vectorworks -- makes great plans, but the elevations and sections need work.

They could have pulled the plug on ADT -- why not, it's nearly dead anyway -- but in respect of the huge user base, development on this moribund product continues.

I say that slightly tongue in cheek because Heathrow Terminal 5 was handled entirely in 3D using ADT. Go figure huh?

[Anonymous]

Miki wrote:
Asking this question I was hoping to get answer like:

-We did 300.000 sqft hospital and we had no problems on plan, but section were generated slow, and 3D was total disaster.

I am working on a 105,000 m2 (1.13 million SF) project: 40 story tower, 31 story tower. and a 6 story podium, each in separate .plns hotlinked into total project file; the towers are built with modules; the publisher book for Design Development is a separate .pln and up to 130 sheets. Details will likely be drawn in Autocad and placed into the layout book. All plans, elevations, and sections are live (manual update) and numerous axonometrics (to scale) are placed as line drawings with notes.

I am working on a 2-year old Dell with 3gb ram and it is painfully slow, I have experienced a few crashes. So slow, that I avoid the 3D window and build VR objects overnight; the entire model will generate on a duo G5 with 8gb ram for rendering in Maxwell Render. The files are set up to be as efficient as possible, but still are loaded with complex profiles for beams, wall, and rails and objects alternate between simple and complex depending on the detail required for a particular view. I expect my computer is soon to reach its limit. Fortunately, my new intel duo arrives this week and I am confident it will handle this project easily.

Talking with a Revit user, I'm told it would be very difficult to model a project of this size.

Mabe

[Anonymous]

That's how you'd do it in Revit too. Mostly it's about the plan sets: each plan set would be generally be one Revit file. One for each tower, one for the podium. The main limitation at present is that Revit will not allow an annotation (e.g. detail section) in one file to point towards a detail drawn in another file, though you could do this with a dummy annotation that you'd have to manage manually. And if you want to put two files together to create a single drawing set you have to manually handle page numbers. Or if you cut a section through a linked file, you have less control over the linked file's appearance. If the model's been built well, you'll get away with it. Let's say you have two coplanar walls of the same type that are side by each, one in each file, and their files are linked. AC will not show a line between these two walls, because AC knows that the walls are coplanar and similar materials, so it joins them. Revit would show a line between them, and you can't edit the lineweight of objects in a linked file.

My suspicion is that AC handles these sorts of things better.

[Anonymous]

The towers are built from stacked modules external to the tower plans. In elevation, there are no lines where they connect if the materials are the same (and they are coplanar, of course.) Are you saying that in Revit, there would be a line at every floor?

Sections are also cut in various files depending on the scale, but the overall section is cut through a composite of all three files (the 2 tower plans are also composites.) In ArchiCAD, beams, columns, walls, and slabs clean up (no visible lines). What happens with Revit?