Some part of mesh not moving with animation in ue4 only

  • this is paragon twin blast character, i converted this to ue4 mannequin skeleton.

  • mesh moving well in pose mode in blender, i.e, mesh weights are assigned well.

  • but in ue4, only a few mesh not moving with animation at calf, problem?

  • Animation working correctly in Blender

Ue4 dumps weights below .01 during import.
Maybe the issue is the area isn’t painted appropriately to account for that.

I wasn’t painted manually,

converted to mannequin skeleton by Vertex weight mix modifier and deleted extra bones.

Doesn’t necessarily matter how it was painted.
Some times the weights can work in a DCC while below the treshold that works in unreal.

I would suggest you start over.
Re-target twinblast to the epic skeleton in engine, then export.
I have done this before on twinblast without issues (Except his base mesh not this exactly alternative, same theory though).

Blender Bug

how blender keeps two vertex groups in Same name?

  • actually two bones, one is thigh_twist_01_l and other one is thigh_twist_02_l,
    I applied Vertex weight mix from thigh_twist_01_l to thigh_twist_02_l and deleted thigh_twist_01_l bone only, but not deleted thigh_twist_01_l Vertex group

  • And renamed thigh_twist_02_l bone to thigh_twist_01_l bone,
    here thigh_twist_02_l Vertex group automatically renamed to thigh_twist_01_l and here blender keeps original thigh_twist_01_l as it is in same name, i didn’t noticed this.

  • one vertex group has some weights and another one has total required weights,
    export/import takes only one, so error came…

  • Deleting unwanted vertex group and keeping required one Solves this problem.

Makes no sense unless you customized the mesh.

The original model already has artist quality weight paint.

Instead of changing that weight paint, you should re-target it and export it from within the engine, so that the weight paint is enterly preserved.

artist made paint is always better than automatic weight paint

  • I’m new to character modelling/rigging.

  • Actually as much as i know, retargetting in engine is for duplicating animations for twinblast skeleton,
    And keep multiple animations separately for mannequin and twin blast and other characters skeletons that i need, is it?

  • If not, I don’t know about the process you are suggesting,
    Could you please provide video tutorial about that.

  • Vertex weight mix modifier is not for automatic weight painting,
    this modifier is for coping data from one vertex group to other, right?

The engine does this by creating a new set of assets - and exporting these assets gets you a mesh that is correctly set up to use the epic skeleton.

It is something I filmed before:

Around 9:27
But not in enough details for beginners.

You have to create a pose for twinblast that matches the mannequin, then use that pose and the same right click process I show in the video on any animation.

After doing that, you can just export the animation to blender.
You go into Pose mode, clear rotation, scale, and translation for all bones or just delete all the key frames.

This will live you with the mesh, and the unreal skeleton bones.

Exporting this mesh out and into the engine, will then create a clean mesh of twinblast with the clean epic skeleton.

No idea.
There’s no reason to copy or alter anything though.

You can literally rename the vertex groups in blender to match the epic skeleton bone names.
Everything would also just work.

Retargeting in engine is pretty easy.
Correctly spelling some 60 bone names is painful…