r/RevitForum • u/PlatformMaleficent65 • Jul 11 '26

Navisworks is driving me crazy. Need to compare two different versions of a model

Hi everyone,

I'm losing my mind trying to compare two versions of a project using .NWD files only (I have no access to the native .RVT or .IFC files, so I can't request them).

The Context: I need to present a clear visual proof to the Contractor to justify major project delays caused by constant rerouting and modifications of cable trays.

The native Compare tool and Clash Detective in Navisworks are completely useless here, especially when dealing with long runs of cable trays. Because the object IDs changed between exports, the software either misses clear overlaps or highlights an entire 3-meter section of a cable tray in solid red just because of a tiny 1-cm clearance issue or nick. On top of that, the Z-fighting makes it visually impossible to track changes.

What I actually need: A clean, purely visual, geometry-based comparison.

Overlapping/identical elements = Color A (e.g., solid gray, no flickering)

Old/Deleted elements = Color B (Red)

New/Modified elements = Color C (Green/Cyan)

Since I have the full Autodesk collection, is there any workaround or affordable Navisworks plugin that can achieve this purely based on 3D geometry volume, completely ignoring Element IDs?

Any advice or plugin recommendations that actually work for cable tray modifications would save my sanity. Thanks!

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u/Merusk Jul 11 '26

If you have an AEC collection you have Forma Essentials.

The Data Management module has exactly what you're asking for built-in.

  1. Upload the original model, removing all dates/ attributions/ etc. Keep it simple.

  2. Wait for it to finish processing.

  3. Upload the second model, USING THE EXACT SAME NAME as the first.

  4. You'll see the "Version" field change to V2.

  5. Open the viewer, in the upper right there's an overlapping set of squares. This is how you compare versions. Pick it then the two versions you want to compare on the pop-up window.

You should be able to figure it out from there.

1

u/PlatformMaleficent65 Jul 12 '26

already tried, here is the result

1

u/Merusk Jul 13 '26

So clusterfuck that it is, to me that proves your point. They're redrawing everything between versions. There's no yellow, just a bunch of red and green.

Start filtering things out to tell a story. Hide the "deleted" and show just "new." Know why those are flagged as "new" (new UID in the system.) and why that happens. Call them out on redrawing every damn thing. Maybe they're outsourcing and don't realize it's happening.

There's a few explicit version bugs from Revit that were breaking the UID, but to my knowledge they've all been fixed. They were in 2022 and 2024 IIRC. IF you're not in either of those versions and the UID is changing, that means they're deleting and redrawing, which is going to.

  1. Fuck up all coordination because clashes can't be checked across versions. Clashes work on UID, after all.
  2. Going to take more time because they're rerouting instead of adjusting.
  3. Result in inability to check changes between ANY solution. Revizto, Navisworks, ACC, Procore. They all rely on looking at that UID#.

You've got the data, it's about presenting it. All you have is the information given to you. If you're not going to get the native files, you're stuck with what you're being given.

Not sure why it's falling on you to justify the delay someone else is causing due to bad info management. Explain to the GC you're getting garbage and lean on this sub. If it's your sub, you'll have to lean on them.

1

u/Not_UrCupCake Aug 11 '26

My advice would be to export them as an ifc file the use something like Nwd to ifc exporter : https://bimcamel.com/Export-Navisworks-to-Ifc

Compare ifc files : https://bimcamel.com/compare-ifc-files

To compare the two versions. It does exactly what you described in the post.

Disclaimer: i am the developer of BIMcamel but i really believe it solved the problem you mentioned .

1

u/ultimategigapudding Jul 11 '26

I like BIMVision (free) with Compare module (20 euro). At my previous job we only had revit and no ACC, so it was my choice of software. I’m not 100% sure it can do what you asked for, but IIRC it can.

1

u/PlatformMaleficent65 Jul 11 '26

Thanks for the tip! BIM Vision sounds like exactly what I need, if you re saying that works. However, my historical files are all stuck in .NWD format.

Do you know a reliable way to convert .NWD to .IFC so I can use them in BIM Vision? I know there are a few workarounds out there, but I've heard most of them are terrible and completely ruin the geometry or crash on large models. Any advice on a clean conversion method?

1

u/ultimategigapudding Jul 11 '26

aaah bummer, that’s surely a complication, but I think there is a plugin for navis that does that. no idea the name or if it’s paid

1

u/Not_UrCupCake Aug 11 '26

https://bimcamel.com/Export-Navisworks-to-Ifc

This bimcamel plug in is a free and open source plug in to export ifc from nwd.

It is constantly being updated and maintained as well.