Using Extended Entity Data

Extended entity data is really nothing more than an extension of the objects regular entity data. By using the procedures and techniques previously discussed for handling and manipulating the association list of an AutoCAD entity along with a few specifically designed Xdata functions, extended entity data can be assigned, retrieved, modified, and even saved to an object with very little effort. Once the information has been saved to an object's definition, then it may be recalled at a later time, long after the initial drawing session has been terminated. This information remains attached to the entity until the information is either removed using a process similar to the way it was attached, or the entity is erased from the drawing. Extended entity data does have one major limitation; the amount of information that can be attached to an entity is limited to 16K bytes.