Property Libraries

What is a property library?

Property Libraries bundle many different appearance properties together with a symbolic name and description.

Why use one?

Property libraries allow a developer to assign many appearance properties at-once, and to do so in a way that is very simple to understand. You might design a material called "oak", for instance, that handles assigning a texture along with a mapping mode and scaling factor, and along with surface colors and rendering properties like gloss. As far as your end-user is concerned, they simply say they want their wood to look like oak and the complexity of their request is handled by the material designer.

Further, property libraries can be reused across multiple applications, cutting down on start-up costs for additional ventures. Once you develop a material called "oak", for instance, you may reuse it with other projects and drawings since the definition for it is in an external property library.

Are they linked to the drawing?

No. Modifying a property library entry after it has been assigned will not affect the appearance of existing drawings. An important reason for this is that to achieve realism you may wish to assign a material, but then introduce a degree of randomness to the surface properties. For instance, you might adjust the scaling factor slightly or the underlying surface color. This will introduce a variation that can keep many instances of the same material from looking too much alike. Imagine a deck, if you will, where every deck board looks exactly the same right down to the placement of every knot in the wood texture. Now imagine the work it would take to develop many variations of every material and to assign them randomly as each deck board is created. When you compare that with assigning a random displacement to an appearance property after assignment, you can appreciate the impact of this decision.