In 3D computer animation images have to be stored in frame buffer converting two dimensional arrays into three dimensional data. This conversion takes place after many calculations like hidden surface removal, shadow generation and Z buffering. These calculations can be done in Image Space or Object Space. Algorithms used in image space for hidden surface removal are much more efficient than object space algorithms. But object space algorithms for hidden surface removal are much more functional than image space algorithms for the same. The combination of these two algorithms gives the best output.
The representation of graphics in the form of Raster or rectangular pixels has now become very popular. Raster display is very flexible as they keep on refreshing the screen by taking the values stored in frame buffer. Image space algorithms are simple and efficient as their data structure is very similar to that of frame buffer. The most commonly used image space algorithm is Z buffer algorithm that is used to define the values of z coordinate of the object.
Space object algorithms have the advantage of retaining the relevant data and because of this ability the interaction of algorithm with the object becomes easier. The calculation done for the color is done only once. Object space algorithms also allow shadow generation to increase the depth of the 3 dimensional objects on the screen. The incorporation of these algorithms is done in software and it is difficult to implement them in hardware.
What’s the difference between Image Space and Object Space
• Image space algorithms are much more efficient than object space algorithms
• Object space algorithms are much more functional than image space algorithms
• Color calculation in object space algorithms is done only one time and is retained by it but in image space algorithm the calculation once done is over written later.