Joint Chains

On this tutorial by Matt I learnt to place joints on a geometry in order to animate separate joints, in this instance we were modelling a simple leg with three joints, the hip, the knee and the ankle.
I simply started by modeling a polygon cylinder and scaling it to roughly a size of a leg that can fit three joints. Placing the joints had to be done on orthographic view not on perspective, otherwise the joints wouldn't line up perfectly.
Working on the 'Animation menu' I had to bind the skin of the model with the joints and by this I went on 'Skin > Bind Skin >Smooth Bind > Smooth Bind Options'.
Under 'Bind Method' I chose 'Closest in Hierarchy' and under 'Skinning Method' I chose 'Dual Quaternion'. 
The other options were fine on default.
After attaching the skin, I began painting in the weights, this helped influence the white, black or the grey on the joint.
To avoid pinching on the knee I smooth painted the geometry using the brush from the tool settings.
What I learnt on this tutorial was to rig joint chains to geometry in order to animate certain aspect of your model e.g a flapping flag or a walk cycle.