Understanding co-ordinates

Question Animation

When a rigged mesh is animated I notice that its X,Y and Z co-ordinates don't seem to change, (either when I look at part of the mesh or the skeleton). This is annoying when I want a camera or light to track the animated object. Is there a way to combat this? 

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  • Martin Aversa(cgtin) replied

    mmm not sure if I follow but maybe use a contraint on the camera to track on the rig?

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  • Omar Domenech replied

    Perhaps that's because you are seeing the transforms or the child and not the parent? When you parent an object, the child retains its original coordinates, and it's the bone that moves and changes the transforms values. 

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  • Jim Coote(jimcoote) replied

    When a rigged mesh is animated I notice that its X,Y and Z co-ordinates don't seem to change, (either when I look at part of the mesh or the skeleton). This is annoying when I want a camera or light to track the animated object. Is there a way to combat this? 

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  • Jim Coote(jimcoote) replied

    I think it might be to do with the animation being made in Miximo. The skeleton and mesh move together in the desired direction, but the origin stays put. I don't think I've noticed that with animations I've made before. No idea why the origin stays put.

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  • Jim Coote(jimcoote) replied

    Weirder still. At frame 1 the origin at 0,0,0 and the skeleton + mesh is 3 metres in front on the Y axis, (even though its co-ordinates say 0,0,0). If I use 'set origin' to 'geometry' , 'centre of mass' (surface or volume), the origin stubbornly stays at 0,0,0. Very frustrating! I've tried changing transformation orientations, but nothing works. It's as if some command has been given that prevents the origin being anywhere other than 0.0.0.  Alt+G doesn't help. No individual bones change co-ordinates. Other objects or empties parented to mesh or armature don't change co-ordinates, (even though they've obviously shifted). I'm at a loss as to how you can get anything to track to a moving animation. Not a big deal with a jog in a straight line, but if an animation is complex it'll be a real pain to manually follow something.

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  • Martin Bergwerf replied

    Hi Jim, 

    That is all, most likely and as you already suspected, because you Imported the Animation from Mixamo.

    That doesn't help you, of course, but knowing it might lessen your frustration.

    One of the experts here, like @waylow ,might be able to help.

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  • Dwayne Savage(dillenbata3) replied
    There are several coordinate systems going when you work with a rig. First there's the world or global. This is the one you seem to be looking at. Rarely is this ever changed on a rig. This is what you see as the origin in object mode. Then there's local coordinates. This defines the reset position of the bones. This is defined in edit mode of the armature. Then there's the pose coordinate system. Sometime referred to as Normals coordinate in blender community. This is defined in pose mode and this is where the animation information is stored for each bone. All bones are controlled by a root bone. This is in the hip area for Maximo if I remember correctly. This is the bone the would be used to move the entire animation if you wanted a jog cycle to go in a circle or anything other than a straight line. This is most likely the bone you want to parent or use a child of constraint your camera to so that it moves with the entire character. 
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  • Dwayne Savage(dillenbata3) replied

    If you want the animation to be centered or aligned with world then select the armature, tab into edit mode, shift+s->cursor to world origin, shift+a to add a bone. Select the bone either rotate x by -90 or go to right side view(numpad 3) and rotate 90 degrees.(R, 90, enter). Then select the root/hip bone of the Maximo rig, shift+select the new bone you added, and press Ctrl+p->keep offset to parent the rig to the new bone. Then you can use the new bone to move your rig around and it will be aligned to the world coordinates. 

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  • Wayne Dixon replied

    Hi Jim,

    I think I can simplify what's going on for you..

    Your camera is pointed at the object container - which never actually moves. The bones inside the armature are the things that move.

    If you point your camera at one of those (with a constraint), the camera will move.

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  • Jim Coote(jimcoote) replied

    Thanks Wayne. Tracking to the hips does work. There seems to be plenty else going wrong between Mixamo and Blender, but at least that's one issue out of the way. I'm hoping that issues with the Mixamo add-on will be solved in 5.0

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  • Jim Coote(jimcoote) replied

    An important PS to all this. Re: issues with Mixamo and Blender. It seems that an add-on I used from GitHub was defective. I hadn't noticed this previously as I'd always imported Mixamo animations set to 'in place' up to now. However those with actual movement did not work properly in terms of editing or retargeting. Fortunately I've found a better add-on, described in this video, that seems to work well:- https://www.youtube.com/watch?v=GN5qgcWwSuc 

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