Biped Axis Conversion

[Anonymous]

Hello All,

I have a skinned biped human model. I need to convert/transform the axis of all the bones in the biped to one general axis/coordinating system. Basically, I want the local coordinating system to be the same as World coordinating system. 

I tried doing this with the pivot but changing the axis in the pivot rotated the hierarchy of the bone structure. Any help guys? 

[ads_royje]

Hi akilarandil,

with Biped this is not doable at all. All the biped tools are relying on these axis.

Is there any reason you need that to change ?

[Anonymous]

Yes. I'm using Urho3D for a model simulation app. I need to have all bones pointed to one proper coordinate system since I will be using quaternion values to rotate the bones. 

[ads_royje]

Have you tried to export Biped as is, as your character in Urho3D ?

If not, that's what I would try first.

I would be very 'surprised' that you 'need' to have all bone axis pointing in the same direction, as world.

That would not be conventional. I've worked with many game engines, commercials and proprietary and never seen that bones would need to aligned that way. That does not mean that Urho3D does not have that requirement as I never used that one in particular.

I had a look at their documentation, I have not found any mention of anything regarding that, there may be, I just did not found it.

I did found this thread here:

https://github.com/urho3d/Urho3D/issues/1221

Where they are discussing an import issue, and the character used in the thread is a Max Biped as is

T.zip and run.zip.

I've opened both of them, and are Max Bipeds, from names and axis alignment.

The issue in that thread is apparently not related to be axis alignment issue but an importer issue.

This is the file (run.zip) I downloaded and opened in Max :

If they 'absolutely' need to be aligned that way, and I would have to do the character,

I found this one provided as example :

https://github.com/Lumak/Urho3D-Assets/blob/master/Models/Swat/Skeleton/Swat_Skeleton.fbx

I would get that skeleton (Swat_Skeleton.fbx) and use it.

That's the 'best' assurance to get thing working if you are 100% sure that this is required.

You can import it in Max and use Max's Ik system to rig it.

Or you can also use position constraints to set the fbx bones to follow Biped rig, and export only the fbx bones.

That is not great to do. 😞

There is no default rig in any software that I know (Max, Maya, Lightwave, Cinema 4D, Blender, Modo) that would give you bones all aligned world.

I am quite sure at 99.9% that you can export Biped as is with no need to convert bone axis to be world aligned.