LEARNING and PRACTICING ANIMATION:

A10   WORKING WITH WEIGHT CONTENTS

The Warehouse Packer
Paired Arm IKs
Why Would a Cube Need a Rig?

A10   WORKING WITH WEIGHT

Use your eyes
Making an effort
The Warehouse Packer

This chap is required to pick up and place each of the three parcels onto the loading chute.   Each parcel has a different weight.   One is heavy, one is middling and the other light.   In the demonstration above, the top parcel is supposed to be heavy but you can choose which of the parcels are heavy, middling and light.
We have covered some of these topics before but I'll remind you of some of the considerations before you embark on this exercise. The character should think before he takes action.   This serves as our first anticipation point.   The character thinks and so does the audience who anticipate what the character will do with the parcels.

The character then moves to place his hands either side of the parcel and shifts his weight slightly forward. As he moves the upper body in order to view the far side of the parcel, his weight shifts sideways to accommodate the change in the centre of gravity. When he then decides to take the weight of the parcel, he anticipates again by crouching down and bending the knees before lifting.   He is over dramatic with his head angle which emphasises the curved action line of the body during the lift.


The PACKER RIG


THE BRIEF
The Warehouse Packer.

Artistic Elements Covered: Timing and Choreography of a Upper Body
Technical Elements Covered: Using Constraints & Use of Advanced Rig


Scene file "Warehouse Packer".   Sequence Duration 8 to 16 seconds

This chap is required to pick up and place each of the three parcels onto the loading chute.   Each parcel has a different weight.   One is heavy, one is middling and the other light.



The rig for this figure is an exact copy of the one used for A08 “The biped walk cycle” with an additional control assembly for working the arm IKs in a unified pair.   In addition, the three stacked parcels have a rig each which enables them to be moved or picked up by the male figure.
If you have worked through A08 “The biped walk cycle” then you won't need to familiarise yourself with the operation of the arms and the IK/FK system.   If you haven't then you will need to go back to this tutorial and work through the sections that deals with the arm movement, “Moving the Arms in FK mode”.
The operational features are as follows:-
The existing IK/FK controls for each arm, accessible from Move_ALL.FK_L
and Move_ALL.FK_L can be overridden by control_arm_IK_ paired_L.Active and control_arm_IK_paired_R.Active respectively.   These two controls which can be identified by the square nurbs shapes grouped within the larger rectangular nurbs frame will take control of each arm when “Active” is set to 1.0.   When “Active” is set to 0.0 then the control of the arm is returned to the normal IK/FK operation.
When bothcontrol_arm_IK_paired_L.Active and control_arm_IK_paired_R.Active are set to 1.0 then the arms will work in unison when the control_arms_IK_paired


If any item or prop that has to be picked up then using a single point constraint together with an orient constraint who's goal locator is grouped into the wrist joint of the rig is the obvious solution.   The problem comes when you want the character to put object down.   If a constraint has just a single goal (usually a locator) then is difficult and certainly bad practice to override it with, for instance an animation curve.   Point and orient constraints should have at least a pair of goals.   “Rigging for Motion Paths” demonstrates how we can use three goals but you can as many as you like with in reason. With regard to each of our parcels, they only have two goals connected to their constraints and that is controlled from the parcel's rectangular selection wire by the channel “Pick Up”.
For instance, for parcel 3 when control_parcel_3.Pick Up is set to 0.0 then parcel can be moved and rotated by it's rectangular selection wire.   If it set to 1.0 then parcel will move to the target cross in the middle of the rectangular control_arms_IK_paired control.   Have a play with these controls to make sure you know how they work.


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