a little light reading required

[dblhelix]

goodnight-stories needed:

looking for technical info with examples on interpolation and pre- & post-extrapolation in a:m?

 

techref: nil

site search: one (candy cane rotation repeat was conclusive)

 

almost feels like i'm missing something here?

[robcat2075]

goodnight-stories needed:

looking for technical info with examples on interpolation and pre- & post-extrapolation in a:m?

 

Briefly....

 

 

Make a few different position keys on an object in the chor

 

 

Go into the curve editor and move them out a few seconds

 

there should be dotted lines leading to them and away from them

 

select one or all in the curve editor and >Curve>...

 

Interpolation method will set the default behavior for splines between the keys

 

Pre-extrap method sets the behavior of the dotted lines leading into the first key

 

Guess what Post extrap will do?

 

Try all the choices and watch how the lines change.

 

 

Pre and post extrap help create other than flat line behavior in non keyed areas. Repeating a motion ad infinitum is a common use.

[HomeSlice]

From page 3 of the Basic Constraints tutorial:

http://www.hash.com/forums/index.php?showtopic=29743

 

Interpolation Method

When you are working with any aspect of the program that creates keyframes in

the Timeline, you will encounter the effects of Interpolation Method. In

computer graphics, Interpolation is the automatic creation of new values that

lie between known values. The keyframes are the known values. The computer

has to guess where an object should be on every frame that does not have a

keyframe. The Interpolation Method is the main clue you give the program to

tell it how to guess where the object should be. There are four types of

Interpolation Methods: Hold, Spline, Linear and Zero Slope. The Default

Interpolation Method for most things is Spline. However, the default method

for the Enforcement property of most constraints is Hold.

 

*Hold Interpolation: This method keeps the the same value from the previous keyframe until another keyframe is set. It tends to make abrupt "ON/OFF" type

changes and creates straight lines with 90 degree angles in the channel view.

*Spline Interpolation: This method is like stretching a flexible rubber hose around keyframes. It generates continuous, smooth movement and prevents an object from having a linear, robotic motion. Spline creates large curves in the the channel view, the farther apart the keyframes are, the larger the curve, and hence the more the object's motion varies from an imaginary straight line between keyframes. It is good for smooth, flowing organic motion.

*Linear Interpolation: This method is like stretching a thin string between keyframes. It makes straight, angular lines in the channel view and creates sharp, jerky movements. This method is good for mechanical and robotic types of motion.

*Zero Slope Interpolation: This method is the love-child between Spline and Linear. Like Linear, it prevents large curves from forming in the channel view, so the movement is more predictable, yet like Spline, it allows smooth transitions from one keyframe to the next. It creates straight lines with rounded angles in the channel view and is good for keeping an object "tacked down" until you want it to move, while still providing fairly smooth transitions.

 

In the image below:

Red = Hold

Green = Spline

Blue = Linear

Orange = Zero Slope

[HomeSlice]

Pre-Extrapolation: Allows you to create some key frames later in the choreography and have the object repeat those movements from the beginning of the chor up through the original keyframes. (I don't think I have ever used this)

 

Post-Extrapolation: Allows you to create some keyframes and have the object repeat the movement from the end of the last keyframe for as long as the choreography lasts.

 

Options are:

Reset: As far as i can tell, it sets the value for the channel to "0" after the last keyframes and keeps it there for the duration of the chor.

Hold: This is the default value. It just keeps the object where it was on the last keyframe.

Repeat: Repeats the motion from the first keyframe through the last keyframe, and cycles the motion indefinitely.

Ping-Pong: Cycles back and forth from the first keyframe through the last keyframe, then reverses the motion, moving from the last keyframe through the first keyframe, and cycles back and forth like the pendulum on a clock.

Accumulate: Basically it is the "Repeat" option with Offsets. It goes through the first iteration, then it takes the last keyframe as the starting point for the next cycle. For example, if you move a camera along the Y axis from 0 to 10 over 24 frames, "Accumulate" will continue to raise the camera along the same vector for the duration of the choreography.

[dblhelix]

so i'm not missing anything, it really is that easy .

that's a constant newbie problem, "is this all, have i questioned enough?"

 

HomeSlice's bit on post-extrapolation belongs in the wiki!

 

Thank you!