3D GLOSSARY

Forward Kinematics Animation
Animation method where the position of a child object in an articulated “chain” are determined by the position and orientation of its parent object.  For example, in a hierarchical linkage of a human figure, when the torso (the parent) bends over, the head (the child) moves along with it, but the head can be turned without affecting the torso.

Global illumination
Family of algorithms wich, when determining the light falling on a surface, take into account not only the light which has taken a path directly from a light source (direct illumination), but also light which has undergone reflection from other surfaces in the world (indirect illumination).

HDR Rendering or HDRR / HDR Lighting
HDR is abbreviation for High Dynamic Range. It´s the rendering of 3D computer graphics scenes by using lighting calculations done in a high dynamic range. Specifically it refers to the new lighting model used to illuminate 3D worlds. Video games and computer generated movies greatly benefit from this as it creates far more realistic scenes than with conventional lighting models.

HDRI
High dynamic range imaging. It´s a set of techniques that allow a far greater dynamic range of exposures than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to the deepest shadows.

Heightmap
A grayscale digital image used to store three-dimensional data. It´s usually used in bump mapping, displacement mapping and for terrain mesh generation. In a heightmap, the intensity of a pixel's color represents the height displacement of the mesh's corresponding coordinate. A white pixel represents the highest point in the map while a black pixel marks the lowest point in the map.

Inverse Kinematics Animation
Animation method that consist on positioning the ending limb of an articulated “chain” to obtain an automatic pose or articulation of the whole chain.
Inverse kinematics is based on the following principles: 1. Joints are constrained with specific positional and rotational properties.
2. Position and orientation of parent objects is determined by the position and orientation of child objects.
Inverse kinematics is often easier to use than forward kinematics and user can quickly create complex motions. However, it sacrifices some of user’s control to the automation of the IK functions.

Keyframe
A frame from an animated sequence, at which a significant animation event or change takes place. In computer animation, the animator defines the keyframes and the computer generates the intermediate frames (process called tweening).