Skinning & Boning The Hand

This week was dedicated to creating bones to put inside the hand which will allow for realistic hand/finger movement when animating the character.

The first step is to create ‘helper’ objects which the bones will be ‘linked’ to so that when a helper object is rotated the bones rotate with it. Under the create > helper menu the correct tool to use is ‘Point’. I placed a separate helper point in front of each finger and he thumb.

The next stage was to create the bones. Under the create > systems menu I chose the ‘bones’ tool and drew out five bones, one acting as the bone inside the palm and the rest for the finger itself. It may be necessary to resize/scale some of the bones to get the right shape inside the hand.

When the bones are ready in the correct places inside the hand I now had to link each bone to the correct helper object. For example each bone along the forefinger will be linked to the helper object positioned at the tip of the forefinger.

I select a each bone in turn and right click and choose ‘wire parameters’ then from the drop down menu I select ‘transform’ then ‘rotation’ then ‘Y rotation’ because I want the fingers to move up and down like they should.

I then click the helper object to begin the link, going through a similar drop down menu box, choosing the same Y rotation selection.

A box appears where I click the middle button and then down to ‘connect’ this completes the link between the two.

Once each bone has gone through this method the helper objects can then be used to rotate the fingers. Furthermore the thumb was also added to the Z axis to allow it to move on its two axis.

The next stage is to link all the bones in the hand to the hand itself so I can move my hand object with the bones.

With the hand object selected I applied the ‘Skin’ modifier and added all the bones in the hand to the modifier. Now that everything is connected the helper objects will now be able to move each of the fingers, however in most cases the skin modifier applies a much too strong pull on all the vertices all around which leads to a messy looking hand object. To fix this I went inside the skin parameters to edit envelopes.

Also within the weight properties there is an ‘Abs. Effect’ which ranges from 0 to 1 and dictates the strength of the vertex select. So by turning down vertices that should be moving to 0 it is easy to clean up the envelopes to animate a realistic looking hand.

I reapplied the ‘Turbosmooth’ modifier to the hand object to give it the realistic appearance and then tested some simple hand movements on the animation timeline to get used to how it worked.

Below is a video of the characters hand.