Why does Unity say "Max can't export to FBX" when I can export to FBX just fine from max?

Questions & Answers
1

I'm using 3ds max 2010 (32-bit). I am working on a mechanical animation that shows the assembly of a handgun step-by-step. The Unity interface allows the user to click "next" and "previous" buttons to see the animation at their own pace. It has been working fine for many weeks now.

My normal work flow has been to save my .max file in the Assets folder of my Unity project. I really like how I can save the file in max, jump to Unity and have the asset update automagically.

Just today, I started having problems. I needed to use a "Link Constraint" in 3ds max to properly animate a couple of parts moving together after they are "attached". So, one mesh gets just a single key at the point where it attaches to the other mesh, and then max makes that part stay "connected" or "follow around" the other mesh that it is linked to. Of course, Unity doesn't respect this, unless I check the box to "Bake Animations" in the options of the FBIImporter for the max file in my Unity project.

Now, yesterday was the first day I tried using "Bake Animations" in Unity and it seemed to be working fine. Today I added a couple more animations that use link constraint, but when I saved the max file and went back to Unity, I got the error message "Max couldn't convert file to fbx" in Unity.

So, I tried un-checking the "Bake Animations" option and hitting the Apply button to re-import. This time, it updated without complaint (but with my animations that relied on link constraint not coming out right). I tried checking the "Bake Animations" box again and hit Apply. This time, Unity editor froze for over 5 minutes (normally it just takes a few seconds to import) until I finally killed it. When I re-started Unity, it said "Automatic import disabled because the importer crashed last time" or something like that (I lost the error message now).

I've tried it several more times, and even reverted to an earlier autosaved version of my file, but with the same result every time: I can import it once with "Bake Animations" turned off, but Unity hangs (I even let it sit for an hour while I went to lunch -- still frozen!) each time.

So while I was doing all that, I also tried exporting to FBX from 3ds max directly. No problem at all. I used the following settings on my fbx export:

Geometry: Smoothing Groups checked, all others unchecked

Animation: checked

Bake Animation: Checked, start frame 0 end frame 1300, step 1

Deformations: checked, Skins checked, morphs unchecked (I use the skin modifier for springs)

Curve filters: unchecked

Point Cache Files: unchecked

Cameras: Checked

Lights: Unchecked

Embed Media: unchecked

Scale Factor: 1.0 (modeled in cm, max units set to cm)

Up Axis: Z-up

FBX File Format: Binary - FBX200900 (I also tried FBX201000)

Every time I export to fbx from max, it works just fine. I can bring the exported FBX into Unity and use it in place of my max file and everything works great (I don't have to check "Bake Animations" in Unity in that case because max already baked them).

So, why is Unity telling me that max can't create an fbx file when max can clearly do so without a problem when I export manually?

I'll be happy to share the max and/or fbx files if that would help.

2

I also have a similar problem which has caused me to lose a lot of sleep:

i have a project with a single max file that holds all the geometry and the animations. everything was working wonderfully until yesterday when i did something in max. since then i get a “Max couldn’t convert the max file to an FBX file!” error every time unity tries to import it. no matter what i try to do - this is what i get. the thing i changed in the max file was really small and nothing that should have made the file so unusable - i flipped some faces, moved a few vertexes around and created a box. oh yeah, i also animated the box. normally, with keyframes for position, rotation and scale. nothing too exotic.

exporting the file to FBX will be the last resort since i don’t know of a way to replace the prefabed max file with the exported FBX and there is a lot of things happening that reference objects from the max file specifically and would be a pain to replace.

i have tried:

  • deleting the object i last worked on
  • breaking up the max file into separate file holding only a few objects each
  • importing the file into a fresh max file
  • doing the import into unity on a different machine
  • spinning around seven times counterclockwise holding a chicken over my head (not really)

nothing seems to help. i am getting the same cryptic message every time, only sometimes it is accompanied with the helpful suggestion to export the MAX file manually to an FBX file. thanks, yeah, i got that.

any ideas as to what could be causing this? i’m on a tight deadline and any help would be most appreciated. also i would like to know what to be careful of when working on the MAX file so this thing would not happen again.

i will also try to post this as a separate question, maybe someone with more experience can help me as it is (hopefully) something like “check that box” or “remove that modifier”…

thanks,

amit