Large Projects / Why is Revit so Slow?

[jj mac]

First off I want to say regardless of the posts title, I love Revit. I have been using it for 4 years now and could never / would never move back to the CAD world - unless I decide to change careers...

With that out of the way, when working on large projects, why is Revit so slow???

What happens along the way in the course of a project, that makes things run so sluggish?

I have seen this happen is every office I work in, I have read countless posts about it, tried purging, auditing, deleting elements manually, fixing errors... everything.

Nothing changes.

There needs to be some guide lines that come from the top, that are tried tested and true, based on results from a real project from the factory. Autodesk marketing needs to stop wasting time on making money on the next release, and fix the issues that we are all struggling through, so that we will continue to use this software in the future. It is the best investment Autodesk can make with Revit. We need you guys work through the issues we are working through and experience this stuff first hand... If you have already done this - please show me the literature to prove it!!!

I will be the first to say that whatever the reason our models are running so slow is because of something that we did along the way to make it so, but we need to know what that thing is and how to avoid it!!! What are the best maintenance techniques besides the ones I have mentioned above!?

My main issue, is that for all of our projects we need to utilize grouping functionality. Some files need to have 50 - 75+ groups in them, just to make editing and managing the file as easy as possible. This should be easy for the software and computer to manage and process Especially with technology being the way it is now!!! Some of our files I can see the groups going wayyy above 75+ groups. But we have to wait for so long for things to change.

My example here, is from a building that has 46 storey's and has one group that contains the typical shell of the building and has 32 instances. When making changes to the group, while in the group editor, things work great. When it's time to finish the group or reload the group, we are waiting for upwards of an hour to see the change!!! And then it comes back with a ton of errors and wants to make new groups!!! This is completely unacceptable. I can't fight to keep this going if this is what I have to show - an hour to change a group. Everyone gets sold on Revit being so fast and so much easier to use. Time to prove it Autodesk.

We all love this software, and we all want to grow with BIM as it develops, but we cannot do it with Revit unless something changes with performance. Every year I hope this will be fixed and it never gets fixed. It's time to fix it. FIX IT! Stop suppressing the technology! Let er go!!! ugggGG!

[Captainkb]

What do you have for PC specs?

Hopefully you have the latest hardware. 64bit, quad core, 16GB RAM.

Revit is pushing the PC hardware limits. 3D is doing it.

46 story building? I would have the latest everything out there for pc hardware.

$7,000 - $10,000 per desktop computer?

[cliff collins]

46 storey building:

1. Break it up into several linked Revit files:
-base/podium
-typical tower stories x-thru x
-upper stories x-thru-x
-tower cap
-Interiors Model(s)
-Structural model(s)
-MEP model(s)
-Site model
etc.

2. Hardware/software:
-64 bit OS
-64 bit Revit
-fast processor ( multi-processors really do not have much impact, since only a few things
like printing and wall joins are enabled for multi-threading in Revit's software code.)
Lots of RAM--8 GB min.--the more the better. RAM is probably the biggest factor.

3. Enterprise quality hub/switch w/ gigabit speed, Cat 6 cabling, good ethernet cards.

4. Dedicated hard drive on server for Revit models

cheers.............

[Scott D Davis]

Worksets to break the model up into chunks. Only check out what needs to be worked on for a particular task. Don't open the whole building file when you are placing toilet partitions on the first floor.

[twiceroadsfool]

What they said. Id be using Links for Floor Plates, not groups. Thats just a wacky amount of stuff that can go wrong.

Ill admit, Revit gets a LITTLE sluggish when updating very large projects... But an hour to update 60 or less group instances sounds like youre doing something profoundly wrong with those groups...

The errors also sound like elements in those groups have ties to outside elements, which isnt going to play nicely.

[jj mac]

Yeah I think it's pretty obvious that something has gone wrong... I want to know what the typical reasons for that are. How can these things happen? Is it groups / families / links / errors

I admit the approach on this file will have to be "updated", and things will need to be broken up, but now we are going to have deal with the file management issues of linking, copy/monitor and tagging through links when it comes time to annotate the model.

It shouldn't be this way. We should be able to have the whole model in one file, if we want...

Thanks for all the responses and advice, everyone. It is appreciated.

[truevis]

I'd avoid using 'based' families as much as possible.

Also the workset/linking tricks that others have mentioned. Once you've used worksets to maximize performance and things are still slow, then you have to start breaking the project into links.

How many people do you have working on one RVT, JJ James?

[dbaldacchino]

Always make sure you're modeling as light-weight as possible (if you don't need 3D families, use symbolid, 2D ones with perhaps just some rough 3D shapes for collision detection etc). Also in my experience and tests, splitting things on worksets does not seem to improve performance at all. All you do is manage your memory better, which if you have plenty of then this becomes a mute point.

Little background on my claim....took a 200MB job that was slow to place a wall in. I opened the central and chose to specify worksets. I closed EVERY user defined workset so the model was blank. I created a new workset and clicked to place a wall. In theory it should have been faster, right? Well, it was just as slow as if I opened every workset.

[Brian Myers]

Have you seen the Model Performance Technical note?

http://images.autodesk.com/adsk/file..._tech_note.pdf

[AP23]

Always make sure you're modeling as light-weight as possible (if you don't need 3D families, use symbolid, 2D ones with perhaps just some rough 3D shapes for collision detection etc).

While this may be the only solution, it truly goes against the whole concept of Revit. Especially now, where Autodesk is trying to get on the design to fabrication wagon, where a higher level of detail modeling is needed, it's questionable if Revit can even play a role.

Somehow, I wonder how Digital Poject manages it's highly detailed models while maintaining performance.