Navisworks General Discussion

Navisworks General Discussion

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Posts: 37
Registered: ‎01-21-2006
Message 1 of 11 (1,841 Views)
Accepted Solution

600 mb NWD file size issue

1841 Views, 10 Replies
03-11-2010 05:17 PM
Our customer has 600 mb NWD. it won't be open at a normal PC with 4gb memory, Win7.
but we could open it on 8gb, Win7 64bit machine.
what is the maximum file size of NWD on 4GB memory PC ?
Posts: 149
Registered: ‎10-29-2009
Message 2 of 11 (1,841 Views)

Re: 600 mb NWD file size issue

03-17-2010 01:08 AM in reply to: intratech
The relationship between RAM usage and size of the NWD on the hard disk is not linear, as the NWD file format employs compression. As such there is no single maximum size; however as you have discovered, a 64-bit operating system enables much larger models to be handled, along with enabling larger quantities of RAM.

I hope that helps,


Senior Software Engineer
Autodesk Ltd.
Active Contributor
Posts: 37
Registered: ‎01-21-2006
Message 3 of 11 (1,841 Views)

Re: 600 mb NWD file size issue

03-22-2010 11:35 PM in reply to: intratech
Thank you for the reply.
I found the file size is dependent to file hierarchy. the customer has 4 area with 4 DRIs. They made 4 NWD, then merge them into one NWD. the file size grows 40% more. so we recommended them to create a single NWD from NWC. the file size is now 320mb, not 600 mb.
Posts: 48
Registered: ‎08-20-2008
Message 4 of 11 (1,841 Views)

Re: 600 mb NWD file size issue

03-24-2010 06:58 AM in reply to: intratech
The limiting factor is generally address space rather than physical memory - you must have enough address space, you can get by without enough physical memory (with some loss of performance). So, you will be able to load much bigger models with 64bit workstation with 2GB (8TB address space) than a 32 bit workstation with 4GB (2GB address space).

It's difficult to say what maximum size of NWD is on a given workstation because it depends a lot on the structure/content of the file. You should have both physical memory and address space greater than between 2 and 20 times the size of the NWD depending on content. Around 5 times bigger is a reasonable guess for most files.

Tim Wiegand
Software Architect
Autodesk, Inc.

Posts: 11
Registered: ‎03-27-2010
Message 5 of 11 (1,841 Views)

Re: 600 mb NWD file size issue

03-27-2010 01:52 AM in reply to: intratech
On what I have experienced so far.

on 32-bit systems having 4GB memory an estimate of 470MB nwd file any more than that gives you the error of that sounds like
Memory limit exceeded please adjust memory to xxxxMB.

on 64-bit systems its different because of the memory mapping.

a more or less technical remedy is to adjust windows boot.ini file by adding /3GB /PAE
the adjustment allows navisworks to use around >3GB memory which can open a nwd file above 470MB.

then again you can always say to your customer to split the files instead and review based on area or something.
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Posts: 84
Registered: ‎12-21-2007
Message 6 of 11 (1,537 Views)

Re: 600 mb NWD file size issue

08-25-2011 02:44 PM in reply to: JeffH_ADSK

I know this topic is over a year old however, I also have been running into similar issues. I'm questioning how some of these files are being put together. For more of my BIM files, I barely reach 500"KB" because I try to keep my 3D drawing simple.

On a project where we are working with several trades, I've notice file sizes that easily are 10"MB" or higher. As a result, when the final assembly files is being reviewed we are in the 100+MB file range.

In my effort to "reduce" the file size, I've found simple AutoCAD files just "NEEDED PURGING" to bring the size down below a megabyte. Has anyone looked into this, or maybe talked about this as a "CAD Standard"?

Milt Fitzgerald (a.k.a. Drafter1981)
Siemens Industries (Full-Time Office Position)
Fitz’ Digital Cad Service L.L.C. (Consulting Business)
Product Support
Posts: 479
Registered: ‎10-02-2007
Message 7 of 11 (1,499 Views)

Re: 600 mb NWD file size issue

08-31-2011 02:39 AM in reply to: milton.fitzgerald

Hi Milton,


It's an interesting subject, how far back should you strip your files before bringing them into Navisworks? Purging Models is one answer but there may be unexpected consequences if you strip back too far. You have several places where the bulk of the model size may come from.


Geometry - Particuarly detailed models, if you have lots of pipes and rounded objects in the model then you can simplify how these come through to Navisworks by reducing the facetting factor, this reduces the detail on the model and may make the pipes look angular rather than round, but can massively reduce the number of triangles saved in the model, reducing file size. Depending on what you are doing with the models this may have a detrimental effect on the accuracy of Clash tests and the quality of Presenter renders.


Properties - Again depending on what you are doing, these may be essential for the Search Sets you use in Timeliner, Clash detective and other review functionality. You need to think about where else might this model be used further down the line, will these properties be needed then. If they won't then purging the properties from the model or Publishing with 'Prevent Object Property Export' switched on (make sure the model can be resaved) will strip the model back.


Additional items - Obviously different file formats have different quirks. For example in the DWG options below, you'll see a range of things you can convert or not into Navisworks, Items that are Off, Frozen, Groups, Text and Views amongst others. This applies to most file formats and can be found in the Exporter Options or if Importing under Options > File Readers. Be careful what you switch off though, if you might need those x-refs later then it might be more difficult adding them as an afterthought.


Navisworks DWG Options


Navisworks Data - As a recommended workflow we would suggest having a geometry and properties NWD or NWC referenced by a master NWF which contains all the Navisworks specific data, allowing easier changes to the native model and more manageable file sizes. Obviously the more, views, materials, clash tests, comments and Timeliner Simulations you have, the more your file will grow, if size is an issue, do you need multiple Master NWF's for different jobs? Does the person who looks after clashes on Level 1 of your building really need the Presenter materials and lighting for the entire model?

Lee Mullin
Product Support Specialist
Global Services
Autodesk Ltd.

Active Contributor
Posts: 33
Registered: ‎01-28-2009
Message 8 of 11 (1,394 Views)

Re: 600 mb NWD file size issue

10-21-2011 10:06 AM in reply to: lee.mullin

In the project I'm working on, I'm seeing drastic slowdowns in my models opening.  I've been opening the .nwf files so I can work on selection sets, rules, and clash reports.  My .nwd sizes on this project are 92mb, 90mb, 4mb, 131mb, 37mb, and 20mb.


I also have a combined model I created from the .nwd files that's sitting at 375mb.


All of them open pretty fast in NWS, even the 375mb.  If I'm opening the .nwd, it's on the screen in about 45 seconds.


I'm running a Dell Precision Quad Core M6500 with 16gb of ram on my laptop and a Dell Precision T3500 on my desktop where i have my models regenerating in the background on an hourly basis.  I actually have two of those computers, the regen routines are split between the two.  The first T3500 has 24gb of ram and the second has 12gb..


When opening one of my 131mb .nwf models on my laptop, it can take up to half an hour to go through all the files.  It contains 285 drawings from Revit and Autocad MEP. 


On my 88gb model, I have 235 drawings from Autocad MEP, Revit Structure, and Revit Architecture.


I definitely think the amount of Ram is a big issue.  My desktop will run circles around my laptop on some models.  The 131mb model is a good example of it.  On the Desktop, the .nwf will open in less than 10 minutes where on the laptop, that same .nwf can take over a half hour to open..


On the 88gb model, they're a lot closer to the same amount of time.



Product Support
Posts: 479
Registered: ‎10-02-2007
Message 9 of 11 (1,379 Views)

Re: 600 mb NWD file size issue

10-24-2011 02:05 AM in reply to: GrumpyGrizzly

Great point.


RAM is a huge issue in general performance, as alluded to in this blog post.


You should find that most of the time spent will be converting the DWG files into a form Navisworks can easily handle. Files from Revit will have already been converted to NWC's. Effective use of cache files can reduce this conversion process as much as possible.

Lee Mullin
Product Support Specialist
Global Services
Autodesk Ltd.

Valued Mentor
Posts: 413
Registered: ‎02-19-2010
Message 10 of 11 (1,359 Views)

Re: 600 mb NWD file size issue

10-25-2011 12:18 PM in reply to: intratech

Another setting that has to be attended are the 

"convert References" in the DGN section and the "convert xrefs" in the DWG version.

Switching this off and appending the CAD files one by one, and only attach the ones you need will increase the RAM needed and the time needed to open an NWF a lot, and the file size of the NWD you are going to create also.

Also, there is a difference in file size beween version 5.0, 2009 and later if you create an NWD of the same CAD files.

2009 creates smaller NWD,s


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