UE4 and a custom Rig

I decided to use the rig that comes with the character (Manuel Bastioni) in Blender, which I know really well, but heavily modified to include my custom bones like rabbit ears (My character is a rabbit girl) and tails and other parts. Now, my question is this. Can UE4 use modifier bones? What I mean is the bones that modify the others to bend like the ears. Instead of bending them all at once I want to IK them to bend with a handle. The same with the fingers and legs. When I animate it I will use the handles to make it easier for me. Can I leave them in or must I remove them?

I don’t understand exactly your question but I can assure you that UE4 can manage any skeleton.
When you export from blender in FBX, the FBX file contain the mesh, the skeleton, the skinning info between them and one animation.
The animation infos are essentially rotation of bones but UE can also manage translation of bones (you have a check box to fill for that).

You can do anything you want with your skeleton in blender (except scaling bones) and import it to UE4.

I am assuming he is talking about bone constraints in blender (he wants to put IK constraint on bones so he moves 1 bone and the other bones follow or a bone that moves the other bones.)

I don’t know for sure. I am not very experienced. Just speaking from what I learned so far. It doesn’t really matter, when you make animations it just saves the location/rot/scale of the bones and not the IK movement. (They are not really weighted to the bone, they are just moving them) Thats just purely for you to see and to make things easy for you. I don’t think it will affect your animations. If you leave the extra bones and import into Unreal they will be in the skeleton. (I don’t think blender constrains work in Unreal engine. They will just be there unweighted.) The animations should work.

If you don’t want the extra bones.

  1. You could just make the animations and the IK constraints in blender
  2. Save everything
  3. Deleted the IK and extra bones
  4. Export
  5. Reload the blender project to how it was.

Could someone confirm this? or you could just try it your self a bit faster.

I dont know how familar you are with Rigify but they have these simple to use extra bones that bend other bones. I call them handles or modifiers, since they modify other bones. Instead of bending my ears, which has 5 bones, I would bend my handle bone (with a custom shape) that does not deform the mesh but it will bend all the ear bones at once, allowing me to easily move them into the typical animated rabbit flop ear. This would also be used for any long tails that I make in order to allow them to swish. I do have Maya but I prefer Blender. I will only use Maya for the Apex clothing animation.

For the record I am not a he but a she, w2lf, I forgot to include something in my sig explaining that.

When you will export your animation, it will only contain the location/rotation and scale infos for each bones you include in.
You can do anything you want in blender to manipulate your bones, FBX will only contain the final result, no matter how you obtain it.
FBX doesn’t embed the IK nor any controler infos, only the relative movement of each bones in the hierarchy :).

If you use a bone to control other bones but have no skinning on it, it will be export and moved but it will have no influence on other bones (unless they are linked to it, of course).
You can choose witch bones you export by selecting them and click “export selected”.

Can you open an FBX directly in blender ? If you can, you should, to look at how it works and what it contains ^^.

All right, thank you. I’ll keep it simple and leave them in since they won’t hurt anything.

Sorry about that. XD my assumptions.

I am just assuming here again. Rigify looks similar to constraints IK’s, from what you described. (I am just not sure if animations work without the extra bones, after you have made the animations. Shouldn’t be a concern if you don’t mind the extra bones like JoGoiA said)

Since I plan on just having finger and ear (plus tails when I make those characters) handles. I’m not planning on going handle crazy :stuck_out_tongue: It’s far easier to bend one bone than to select 3, 4, or 10 bones. Plus, I would like to bring in a cat that I made for second life with an advanced rig and this answers the question I had about it. Yes I can use my little Sparta in my comic/game.

But it raises another. What about custom bone shapes?

Custom bone shapes are only used in Blender. There are no control rig features in UE4 right now, but it seems like 4.16 will have an in engine control rig.

I don’t know what’s a “custom bones shape” but in a FBX file, a bone is just a point and a length. If you need them to have a “shape”, you must make a mesh and skin it to a bone.

I know how to make bone shapes in Blender, they are normally faceless shapes that represent the bones like the image below, which is a quick job from me to create a finger/ear bend IK shape.
I made a plane, deleted the face, subdivided a line and extruded the point to make the handle. Now all I got to do is asign it and I have my handles. They are often on layer 20. Layers are rather unique to Blender, along with the wonderful 3D cursor. Two reasons I am loathe to leave Blender. I am so glad I decided to learn Blender. :smiley: