Large FBX imports easily into Unity, locks at 75% importing into Unreal 4

I have an FBX file that started out as a Solidworks CAD file, which was converted to FBX using a 3rd party converter. If I open this file in Unity, it opens reasonably quickly and displays / renders fine as well. If I open this same file in Unreal Engine 4, it starts to import, then gets to 75% and locks. My processor is still in use, so it appears to be crunching something, but even after more than a day it still has not finished importing, and is still stuck at 75%, “Importing FBX Mesh”.

The file is about 140 MB in size. A smaller file created in a similar matter, but is only 6MB, imported fine.

Unfortunately, due to the proprietary nature of the file, I can’t post it to a public forum like this, so I would need to submit it directly to Epic for analysis. Is there some way I can do this? Maybe an email or even a fee-based support option?

Note: I did find another forum just for posting problematic FBX files, which I have attempted to post to a couple of times, but my posts don’t seem to show up there.

I’m really loving Unreal 4 on so many levels, but this is a case where I will be forced to use Unity if there is no solution for this :frowning:

What is the situation? Does it have a large poly count? If you’ve got a single object with a large poly count then that’s not going to work well for a game even if you import it correctly.

Hey ,

I do a lot of FBX troubleshooting and import for our support team. If you’d like you can private message me a link to download and I can take a look at it when I get into the office tomorrow.

As a note, as Darthviper noted larger files can take a bit longer to import, but once they do they should be OK for the most part. Part of our QA engine pass is importing a 1 million poly file and I’ve imported a 16 million poly FBX that was ~ 600mb which took about an hour and a half with my work system.

Either way, I don’t mind offering some assistance. :slight_smile:

I’ll message you in a few.

Hi Darthviper107 - yea, it’s fairly large. I’m using it for CAD visualization, as opposed to a game, so can rely on high end video cards and such, so performance is not my primary concern. Right now, I’m just trying to make a proof of concept for an idea that if accepted might justify the work of re-optimizing and breaking the CAD model down into smaller components and such.

I was finally able to get it to import by disabling the option “Combine meshes”, which results in importing 6000+ individual meshes. At that point, if I select them all and drag them into the viewport, it renders reasonably quickly, though is not very easy to work outside of the viewport. My attempts to re-combine them back into a single more manageable mesh, though, have so far just locked up the computer. from Unreal has promised to look at the files, so if there is stuff to learn from that, I’ll be sure to post something back here. My suspicion is that Unity just does a simple “combine all” behind the scenes, without bothering to clean up messy geometry or eliminate duplicate or hidden triangles, while Unreal is doing more work, and getting stuck in a loop or something. I’m just guessing at that, though.

If you’ve got a bunch of individual meshes you can try importing groups of them as separate files

I’m having exactly the same issue. I have a large file which was in OpenSceneGraph. I converted it to 3DS then imported it into blender and converted it to FBX. The FBX file is about 112 MB. Importing get’s such at 75%. Using “Combine meshes” get’s more progress but then it keeps complaining about tangents with no option to don’t ask again. It got about 10% through after about an hour and then crashed. It imports fine into Unity.

This is not for a game. This is a demo for industry.

If it’s a bunch of objects, then separate them into more than one file. Also, make sure to disable the option to build new lightmap UV’s on import, since that can slow things down.

In the past I’ve tried to use some models exported from Solidworks and Inventor. When I looked at them in Max I always had to do a LOT of manual cleanup of the mesh. One of the big problems is ridiculous N-gons, and ideally you want quads and tri’s. I’m sure the UV’s will probably be a mess too. The problem is that parametric solid modelers are so very very different from what we use to model game/entertainment/art models. If you start talking about UV’s, edge loops, polygons etc to most(not all) CAD guys you will most likely just draw a blank stare, they almost never have to worry about any of this stuff.
Anyhow, check your topology, its likely a real mess.

Its been a while since the last post, but ill pitch in with this question. I have a 0.5gb fbx file ready to be imported into UE4. The file contains 3000 elements with probably more poly than I want to think of, but oh well. I’ve passed it through 3dsmax from revit, added an additional UV channel to everything with the steamroller script. Without the extra channel, the file took about 10 minutes to import with combined meshes. Is there some kind of plugin that I can use to handle my giant file?

Ive posted a thread on a revit->3dsmax->unreal workflow
Check out my channel @anonymous_user_35a6d4e3]( check out my progress on the fbx import


You can speed it up by disabling generation you don’t need, things like Auto Generate Collision, Build Adjacency Buffer, Generate Lightmap UVs, don’t compute normals, etc.

The upcoming Unreal Engine for Enterprise (4.12 I think) might improve the speed of importing things a bit: - YouTube

You sure there is no dialog box hidden somewhere asking you to confirm something? Could you potentially attach the file and see if others can open it?