Thursday, April 7, 2011

Persistence of Vision

While driving back home with Navaneeth , we struck a conversation on  Film ..not the movies but the actual Film reel or tape ... our conversation was carried on to film frame rates like  24 , 25 , 30  etc ..and from there Navaneeth started to break  these things down to simpler form ..  so  before getting in to 24 25 30 Fps .. he asked me to read up on PERSISTENCE OF VISION..which I have been  doing for about some time now ..so I thought I like to share that with the rest of  you ..

How is the Illusion of  movement is achieved when none is present ? In other words   how do we see a seq of images and feel that  its movement ?

This marvelous phenomenon is known as the persistence of vision and it is through this that we experience moving images made up of frames on a film strip. The secret of this illusion is be found in the remarkable capability of a part of the human eye, the retina, of momentarily retaining any image it receives.
Imagine, if you will, a light being shone into the eye only briefly and appearing on the retina as a bright spot. This bright image would appear to remain for a brief period even after the light had been turned off. It’s this slight period of retention or delay that allows for separate sequential images, if seen in quick succession, to appear as a moving image, and it’s upon this principle that film and video projection works.

1765 by the Frenchman, Chevalier D’Arcy, that it was established that this retention period was approximately one-tenth of a second. The early optical devices that were developed and began to appear in the first half of the nineteenth century clearly demonstrated this effect. What started out as serious scientific investigation soon found a practical application for entertainment through the use of such devices as the thaumatrope, the zoetrope, Joseph Plateau’s phenakistoscope and Emile Reynaud’s praxinoscope. Variations of these quickly began to appear as popular parlor toys in the homes of the upper classes throughout Europe. 

Wednesday, April 6, 2011

Whats is the difference between Settle and Cushion 2

Here is something more I found about the  question Binu  asked  yesterday :

 Ease In, Ease Out:
Also called Slow In, Slow Out. This is a technique used to ‘cushion’ the animation when going into a pose or coming out of a pose. It’s achieved by adding more inbetweens that favor the pose that you want to cushion. Often used to avoid any hard or sudden stops, or instead of an Overshoot.

Whats is the difference between Settle and Cushion

Yesterday  one of the Trainees asked me this Whats is the difference between  Settle and Cushion .. as far my limited knowledge is concerned .. I know that they are about the same thing .. But never the less I  did a bit of browsing around and  found this  on  Animation Mentor .. the  extract below is from Animation Mentor and  Shawn Kelly talks about the same thing .. Hope this  helps !

Could You Explain the Animation Terms Cushion and Settle?

These terms are used almost interchangeably, and mostly they just refer to how a character's movement is going to come to a stop.

Cushion is pretty much the same as "ease in" or "slow-in," animation terms used to describe the way a character will "ease" into a pose or "slow" into a pose. You could also say that a character should "cushion" into a pose - it's pretty much the same thing, as far as I know.

The point of those terms, by the way, is to help sell the organic nature of the character or object. Very few things in nature come to an instant stop on a dime, mostly things more in organic arcs and need time to "cushion" into the final position of their movement. For example, if you were walking quickly and came to a stop, no matter how hard you try to stop instantly, you simply cannot do it. Your body is going to have to recover from the movement and part of that is going to be easing into that final stopped pose (and probably going THROUGH that final pose into an overshoot, and then arcing and overlapping back into the final pose).

"Settle," to me, is very similar. I hear people use that term to describe all of those little overshoots and arcs that eventually run out of steam and lead to the character being still. Picture again someone coming to a stop. Well, their hips are going to keep going until their weight and angle of their body slows them down. The hips will probably sail right through that "stopped" pose and go a little too far before your body says "hey hips! Come back here!" The hips are then going to arc back and go into a bit of tiny spiral that will eventually get them into a stopped position.

Force and general body mechanics tell us exactly what will happen next, which will be a subtle wave action through the spine, causing overlap on the arms, successive breaking of joints going all the way down to the wrists, probably a bit of overlap on the head, etc. - all moving in related arcs in multiple axis, though offset from one another, and so forth.

To me, all of that "stuff" that is happening - all of that is the "settling" of the character.

Other folks might use these terms differently, but those are the ways I've heard them used around the studio. Hope that helps!


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