Problems importing FBX from Maya 2014 to UE4

hello everyone,

i’m new to UE4, currently having export-import problems from Maya 2014 to UE4:

in Maya, the character geometry isn’t a single mesh geo, but consists of lots of geo fragments like this hierarchy:


  • geo_group01
    • geo01a
    • geo01b
  • geo02
  • geo03
  • geo04
  • geo_group02
    • 80 geos
  • geo05
  • geo06

for rigging, I used Advanced Skeleton autorig plugin. it automatically created hierarchy as follows:


  • Main
    • FitSkeleton
    • MotionSystem (FK + IK joints, controllers)
    • DeformationSystem (default bind joints + additional facial bind
      joints + accessory joints)

when i finished rigging and skinning and tried to export the fbx, there were Maya warning and error messages as follows:

Exporting T-Pose FBX (‘Animation’ unchecked):

Warning: Complex animation baked (1)
537 attributes had complex animation. Complex animation was exported as baked curves.
(112770 evaluations done)

then I ignored it and continued importing the FBX from UE4, which gave me warning messages:

  • when importing Skeletal Mesh (the T-pose FBX):

Multiple roots are found in the bone hierarchy. We only support single root bone.
Multiple roots found
Import failed.

  • when importing Animation FBX:

Imported bone transform is different fromoriginal. Please check Output Log to see
detail of error.

  • the final results:
  1. the char is lying, not standing (it seems like Y-up and Z-up axis switched). I had tried to change to Z-up axis in Maya, then rotated the lying character to standing, but it didn’t make the character stand

  2. head geo is missing, but hair geo, which is a separate fragment, isnt

so how do I fix these issues?
your suggestion is appreciated with thanks. :slight_smile:

I’ve never used “Advanced Skeleton autorig plugin” but it may not be acceptable for games. About all game engines (including UE4) require all of the bones to be connected up the line to one root bone. If that system has multiple root bones, then it will not work.

**Are you aware of ART (Animation & Rigging Tools) that you get for free included with the Unreal Engine? **

ART is a Maya plugin that can allow you to easily make rigs for your models. It is made by Epic especially for UE4, so your rigs will almost always work correctly and be facing the correct direction. Since you have a compatible version of Maya, I highly recommend that you start using it.

thanks Vega+, I’m aware of ART.
but my animation team decided not to use ART and create rigs traditionally instead. since I have almost 0 knowledge about character setup, I chose Advanced Skeleton, that speeds up my rigging task.

Advanced Skeleton created 3 group of skeletons, one of them is the binded/skinned joints.
I had baked the animation and exported only these skinned joints and the geometries.
do I need to delete the rest before exporting to FBX?

Yes I believe that is the correct solution. The other skeletons are possibly FK and IK rigs?

In any case, once you bake the skeleton that is binding the skin to joints, you should delete the other two before export. Hopefully this solves the issue.

too bad, although the binded/skinned bones are baked, the geometry deformation is damaged after the FK, IK rigs and controllers are deleted.
it seemed like the scale of the bones are altered.

I check the INPUTS attributes on channel box of a spine bone, there are:

  • ScaleBlend_boneName_M
  • volumeBlendSpineBlendTwo_M
  • multWithStretchSpine_M
  • volumepowSpine_M
  • IKCurveInfoAllMultiplySpine_M
  • IKCurveInfoNormalizeSpine_M
  • IKCurveInfoSpine_M
  • charName_Bind_Joints

these attributes are automatically created by AdvancedSkeleton.
how do I delete them without damaging the binded/skinned bone deformation?