Rotational Axis
These axis describe movement in space within a RT3D engine.
Pitch, Yaw, and Roll
Pitch is red, yaw is green, and roll is blue.
Pitch
Most RT3D engines count from 90 to -90 degrees, starting out pointed straight up, turning downwards and ending pointed straight down. If you nod your head "yes," this is pitch in action. Straight forward is 0 degrees. Also called declination.
Yaw
Most RT3D engines count from 0 to 360 degrees, starting out pointed straight forward, turning clockwise and ending pointed straight forwards again. If you shake your head "no," this is yaw in action. Straight forward is both 0 and 360 degrees. Also called azimuth.
Roll
Most RT3D engines count from -180 to 180 degrees, starting out twisted upside-down all the way to the left, turning clockwise and ending twisted upside-down all the way to the right. If you tilt your head to read the spine of a book, this is roll in action. Straight forward with no roll is 0 degrees.