Blender to UE4 basics ?

Development Character & Animation
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I am sure it’s been discussed many times, but is there a final doc/wiki explaining quirks of Blender to UE4 workflow ?

For example, Blender has X axis as axis of symmetry for animators. So character in Blender would have to face -Y axis in order for animator to be able to animate efficiently and copy/paste mirrored poses. I am sure character has to be facing +X in UE4. How do you resolve this problem?

How do you export each Action into a separate FBX? (in a batch, not manually one by one)

What’s the naming convention for bones?

In what scale should I work in Blender in order to get static and animated models to show up in UE4 appropriately ? (maybe there is a template .blend file with scale set up?)

For any motion (walk/run/jump, etc.), does the root bone have to move or should it all be done on-spot ?

Thanks.

1 Like
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ok here’s the wiki link to set up the scale A new, community-hosted Unreal Engine Wiki - Announcements and Releases - Unreal Engine Forums
here’s a link to my blender ue4 channel Blender Tutorials - YouTube

basically any rig you create in blender will need custom/re-targeted animsdue to the differance in the axis

in general most game anims are done on the spot eg no root motion

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-Y axis is fine, you don’t have to change anything.

You’ll have to write a script for batch export.

Dots . get converted to _ in UE4 so you could use _ instead in Blender.

For the scale use metric with 0.01 unit scale and make sure everything has applied transforms.

The motion depends how you want to do it, normally you would leave the root in place and do the movement with blueprint stuff. For root motion in Blender you will have to cut the animation from the root bone in the rig, then insert a keyframe on the armature object, then paste the animation.

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Thanks folks!

Ouch. Hasn’t anyone written it already?

Could you please elaborate? Sounds kinda odd.
Do I animate Armature object itself for linear motion (walking forward for example) and then go into Pose model to animate actual walk cycle using bones (as if I would naturally do for on-stop animation)? How would that be exported to FBX properly?

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Why is that? Because of difference in where character would be facing in Blender and UE4 or is it generally the workflow for any 3D app ?

How would you fight feet slipping with such approach ?

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I’m exporting anims with this settings (they are from 2.75 but looks the same in 2.76 spread over a few tabs now):

export_screenshot.jpg
export_screenshot.jpg243×766 48.9 KB

I had this at -Z forward and Y Up as others previously as well (and did not notice any issues so far). But after discussing with some other guy in this forum I found a difference if I look to the axes into Visual Studio so I’m using Y forward Z Up now (only at export - so no issues at mirroring while modeling/animating).

If I export a static skeleton mesh I tick on NLA strips and All Actions (depends)…

Regarding the root bone. In place walk works well if you just move the pelvis (hips) bone. Using in place is easier if you would create a multiplayer game (it’s easier for you and it seems it easier for the engine regarding prediction I guess). Anyway there is some issue (or I’m not sure if it’s any issue at all) with a root bone that is a real root bone in Blender if you export it because you would get the armature name as first bone and the real root bone as 2nd bone in UE4. It did not hurt that much if I use in place again. You could still retarget this way if you ignore the “my_armaturename_bone” and can push around the character with ragdoll physic or put it back into it’s capsule cage in UE4 but I’m not sure if this would cause any offset issues on large maps if you do … dunno … some motion that keeps your first bone (armature name) at 0.0.0 while you carry the root bone (as second bone) to another island farer away then float-type would like to keep precision.

Edit: mixed static and anim export settings…

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ref the axis issues its just the fact that blender and unreal use different systems eg lefthand / righthand system , which basically means the Y axis gets mirrored

export settings depends on which version of blender you use, the 2.77 test version is different again, just make sure you untick the add leaf bones as ue4 doesn’t need them

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Nope, but I wrote a hacky one just now, it will export all actions in the file so be careful, also you’ll need to select the armature. The files are exported into the blend file’s folder.



import bpy

path = bpy.path.abspath('//')

for action in bpy.data.actions:
    bpy.context.active_object.animation_data.action = action
    bpy.ops.export_scene.fbx(filepath=str(path + action.name + '.fbx'), object_types={'ARMATURE'}, bake_anim_use_nla_strips=False, bake_anim_use_all_actions=False, add_leaf_bones=False, bake_anim_use_all_bones=True)

Sure. Normally you would animate your root and everything in pose mode if you’ve got a root bone. But since the armature is turned into a new root bone at export you need to either do what you did, which requires you go to from pose mode to object mode, or just use the root bone in your rig and then copy paste it to the armature object animation, then delete the root bone animation in the rig itself. It exports fine.

9

Hello

A bit late to the conversation but I have a very basic animation tutorial up on my channel. One video I want to share is a bone scaling problem I picked up when exporting from Blender to Unreal. You can watch the video below.

There are more videos on the channel and more on the way. If you need more help feel free to ask.

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Hey Geodav, do your tutorials still apply to the current version of Blender/UE4?

Thank you!

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I don’t know about Geodav but I find that not much has changed regarding the FBX exporter. From about Blender version 2.64 - 2.76b nothing has really changed. Also importing I’ve used Unreal 4.6 all the way to the new 4.11 preview.

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Hi Travatron, as far as blender to UE4 via fbx the main things that have changed is the layout of the exporter plus the addition of some annoying default options like “add leaf bones” and the fact it addes the armature as a root bone !!!
a part from that not much the work flow remains the same, just check the update video ref size/scale/unit settings

i may do an update vide when 2.77 is released, tried the lastest build last week but some of the fbx options don’t seem to do much for us