A Card­Board Box Affair

This ani­ma­tion exer­cise is part of a series of assign­ments I will be giv­ing my stu­dents.  Being able to ani­mate action that feels com­pletely nat­ural can pro­vide very use­ful lessons in physics.  In order for an ani­ma­tor to be suc­cess­ful in this assign­ment they must have a good under­stand­ing of Newton’s Laws. They must work to cre­ate a nat­ural sense of tim­ing.  They must cre­ate mul­ti­ple sub­tle vari­a­tions of force based on height and inter­ac­tions between the falling boxes.  They will explore cause and effect and over­lap­ping actions as well as the rest of the prin­ci­ples of ani­ma­tion.  It also serves as an exer­cise in ani­mat­ing an object that bounces and set­tles in like a ball yet has cor­ners and edges.

Final Ren­der

The first pass has been keyed with an even tim­ing on fours. Curve Inter­po­la­tions at this point are set to STEPPED.  All I’m look­ing for dur­ing this pass is the basic ele­ments needed to tell my story. The motion at this point is at it’s most prim­i­tive level.  Your Keyframes should com­mu­ni­cate the (Beginning/Middle/End).  This is called Block­ing in the Animation.

Pass 1 — Stepped

For the next steps the prin­ci­ples that need to be devel­oped are:

• Tim­ing - Ease In Ease Out — Arcs — Set­tle In
  

Pass 2 — Linear

My sec­ond pass now con­tains all of the contacts.  I have changed my curve inter­po­la­tion to Linear.  I like mov­ing into this type of curve cal­cu­la­tion because it helps me to see the tim­ing of the actions in it’s base form.

With a con­stant rate of change: If the character/object seems to move to quickly then the keys that I have set need to be spaced out so that the action will hap­pen over a longer period of time.  Remember.… If a key had a voice it would say: “Be in this posi­tion at this point in time”. If the character/object seems to be mov­ing to slowly, then the keyframes need to be brought close together in time.

First Edit: I changed the tim­ing in the begin­ning by com­press­ing the first few keyframes so that they are in twos.

Sec­ond Edit: Added Keys for the top box to hit the cor­ner in the back then the first edge and then flat. Made the set­tle in faster by chang­ing the tim­ing to two frames for the last hit and stop­ping point.

Third Edit: Added a few keys to the mid­dle box for the extra cor­ner impacts and a few slight rota­tion and dis­tance tweeks.  The tim­ing for the impact to the stop­ping point was sped up so that the keyframes are on twos.

Fourth Edit: Went back and extended the first frame of the top box so that it is on 8eights for a long ease out.  Not happy with the rate of fall.  It should drop harder because it starts out higher than the mid­dle box.

Pass-2a

Fifth Edit: Move the top box keys for the first hit and the set­tle in onto twos and ones for intial look of a harder hit..

Pass — 2b

Prin­ci­ples to Focus on:

1.) Tim­ing
2.) Antic­i­pa­tions

Prin­ci­ples to be devel­oped further:

1.) Con­tinue devel­op­ing tim­ing
2.) Ease In / Ease Out — Hard In / Hard Out
3.) Arcs
4.) Over­lap­ping actions

Pass 3 — Spline/Plateau

I have decided to start key­ing in the box flaps sec­ondary move­ment.  I have been spend­ing a fair amount of time get­ting the right tim­ing and over­lap for them to feel nat­ural.  I am stop­ping to put in the break­downs for the boxes.  Then I will con­tinue to tweek the box flaps.  Notice the pop that hap­pened with the bot­tom box flap… This is ok at this point because I will con­vert to spline later and tweek further.

Break­downs:

I have put in my break­downs and have decided to go sub­tle with them.  This is sup­posed to be a nat­ural box fall and set­tle in.  If there was to be more char­ac­ter I’d push them fur­ther but for now I’m leav­ing them where they are.  I have con­verted to plateau to see how things look… Still looks  good so now it’s time to over­lap some be off­set­ting keys and break­ing some tan­gents to get things to accel­er­ate into the contacts…..

• Over­lapped to cre­ate small slides and the end of the boxes set­tle in.
• Eased up on the bot­tom box with it’s rota­tion and slide… about half the dis­tance and turn…
• Added a keyframe to extend the break­down on the top box… this give a lit­tle hang time…..
• Off­set the box flaps in on the bot­tom box because they needed more over­lap and they were tweening…

Pass — 3a

• Over­lapped the mid­dle boxes star of its fall two frames later….. feels better.

Card­board Box – Pass 4

Now it’s time for the curve tweek­ing process.  I went in and broke tan­gents that I did not want to ease in.  Gen­er­ally you would do this for any motion that needs to me a medium or fast accel­er­a­tion into an impact.  I cre­ated some over­shoot by pulling tan­gents and allow­ing it to accel­er­ate through a key and then return to a then next. Some tan­gents will be flat between two keys… I didn’t want for it to hold still but to be more of a mov­ing hold…. Exam­ple: The top box holds a lit­tle before falling.

Pass — 4

Pass –4a (curve tweeked)

• Still see some­thing that I don’t like on the bot­tom box flaps.  Need to look closer at that.
• Fixed the flaps for now and then pushed the hold on the mid­dle box for two frames.  I think I’m going to let this right for now.

Pass — 4B

• Next, to see if there are any inter-penetrations.  I found a few to fix!

Fin­ished

Final Ren­der is at the top of this post.…. Enjoy!

Craig Bow­man