link fixed sorry for that :)

Made motion paths of hands/arm and "bag". Not sure how they fit together.

@user2859 but can I connect them together to be one armature and export them as a single bvh.?

@user2859 yes, what I want is to connect the hand bone of the skeleton with the bone of the bag then make them one armature, but each has its own animation. Is that possible?

As I said, it is technically possible, but there is too little information how the tracks fit together right now.

Isn't it possible to overcome this with grabbing using 'G'?

As a unrelated site note, if you just want to animate the bag, you could try rigid body physics.

But I can't do this without physics engine? As one of my aims is not using it and instead combine it with the human armature as one bvh where each one of them has its own animation

@user2859 could you share with me the blend file of using physics you did the video please? :) it seems pretty cool and if you could make a quick video how you did it then that would be perfect! And I would be really thankful. I really appreciate your kind assistance and support

blend available, basic instructions included.

Thank you very much! much appreciate it. Will check it and let you know!

can we chat please?

I've done the steps but the bag keeps falling

here is the file dropbox.com/s/sc6bdpy0qsun7gr/physics-bag.blend?dl=0

I don't know what is the purpose of Cylinder.Upperleg.RigidBody and Cylinder.Lowerleg.RigidBody?

That are collision shapes to avoid the bag from penetrating the leg.

oh okay

thank you

and why the bag keeps falling?

and what is the purpose of Cube.Hand.RigidBody?

@user1460166 its to build a rigid body constraint. You need at least two rigid bodies to glue them together.

oh okay

so you glued the bag to it so that it doesn't fall?

well that is one part of the constraint. it depends on the type. i've choosen generic spring, so i had to lock the location too

okay

so could you please have a look at my file at tell me what's wrong?

Will take a while

okay

okay

no worries

so free the bake

okay

btw

in the rigid body world settings

when I do bake is this bakes everything?

or just things related to the selected object?

bake all dynamics bakes everything for rigid bodies

its global

okay

second thing

so i did free bake

your bag mesh is not aligned with the objects center

that is a problem

mmm

okay

because the collsion hull is calculated from the objects alignement and center

so how to fix this?

first select the bag

okay

then, object -> transform -> origin to geometry

in the 3dview header

yup

done

another thing is, that you rotated the mesh instead of the object

go to edit mode

select all vertices and rotate them back

to be horizontal?

they need to be aligned with the green wired box

yep pretty much to align with the objects axis

usually adding a new cube would be easier but just so you know what is wrong

actually this was my problem

another thing

like I added a new cube for the bag and then made a translation to place it on top of the new bone

then added the new small cube

you forgot to enable the location and angle limits. Tick the buttons with X,Y, Z for all except spring

and translated it to the joint of the wrist

but I did all that manually

you can do that, but not in edit mode

it will mess up your collision shapes for simple shapes

mesh and convex hull are exceptions

but they are computationally more expensive and less stable

basically rotate and translate in object mode, always apply scale, but never rotation and translation

oh okay

I always apply all

ctrl+A

then choose all the three

that's bad in this case, because that will align the collision shape with the world axis

the collisions shape is the green wired stuff

if it doesn't line up with your object, that is generally wrong

but how to line it up perfectly?

well, in this case it's just a cuboid

so you can select every face and scale it along the world axis closest to its normal

is generally hard to fix, because applied transforms are destructive

okay

I will delete it now quickly and do it again

usually you want collision shapes only for simulation as a placeholder for more complex objects.

okay

I did all it over again

will send you the file to have a look

1 sec

dropbox.com/s/sc6bdpy0qsun7gr/physics-bag.blend?dl=0

I baked all dynamics

but the bag is making funny rotations not smooth like yours

Yep, though the imported bvh seems to jitter a lot

so the problem is in the bvh file?

I think the funny rotation part can be solved by aligning the constraint object straight below each other.

I don't know how

I already did it

they are pretty close right now

so

but then when I set parent the cube became very very small and rotated

if you drag the bag, you should see a dotted line

yes

I do

shouldn't be parented

ok

the line should be straight in frame 1

aligned with the z axis

what do you mean by that?

sec

sorry for being amateur

I'm just new to blender

no worries

take your time

best go to orthographic view

front view and side view, both aligned to the z axis

how to make this "front view and side view, both aligned to the z axis"?

sorry, i meant the objects should be aligned, so that the constraint line is straight along the z axis. So go to front view, align to the axis, go to right view, align there again.

about the jitter, well you could use the curve simplify, like i showed in the video.

okay

I don't know how to align an object to an axis

do you mean just rotate manually?

and you are talking about the green box object right?

yes, but not only

see the image above

the orange line from top to bottom

the dotted line is parallel to it

oh okay

mine is inclined

it's to set the simulation in a valid state

how to make it straight?

the constraint?

this dotted line

just transform the bag right?

yep

you could use "mainpulate center points"

where is that?

select the upper cube, shift s, cursor to selection and scale 0

sec

and then

?

select the bag and click that?

or what?

Select the upper cube

Shift S

Cursor to Selection

Yeah I did that

S AXIS 0

scale 0 ?

this will make it disappear right?

you need to select the bag also

and choose the right direction!

e.g. in right view

S Y 0

but scaling to 0 will make the object dimension disappear

I think I'm miunderstanding what you are saying

sorry for that :/

my fault

I'm trying to learn

They can not disappear when you have "manipulate centers points" enabled

this only works in object and pose mode

talking about object mode here

and no worries

yes

I did it

thank you :)

Can I ask you where are you from?

germany, i know, my english sucks

hahhaaa

no not at all

yours is excellent

that's great

I was in Germany last Jan

went to couple of cities

but mainly in Hamburg

Anyway, I was just asking as I wanted to send you a postcard gift or something from here for your kind assistance

there is still on problem with this simple setup.

what?

it doesn't distribute torsion right now.

for that you would need to build a more complex setup

i'm thinking about it

okay

please let me know if you have any other thing

and thanks again for your kind assistance

ok found something

you could guide the bag with another spring constraint

this time no limits but springs enabled

will upload the file

before and after activating the guide, blend file

the bvh jitters but the physics looks stable.. so just a little cleanup and it should be good.