Symbols are actually groups of graphic elements with defined behaviors and properties that are saved in an .sym document. You can enhance a symbol's display and performance during symbol design and creation. Incorporating a fill with blank color into the symbol allows the symbol, when placed, to mask out elements such as lines or connectors that intersect the symbol. This gives the appearance that the underlying lines have been broken at the edges of the symbol. In reality, the lines still exist beneath the symbol.
You can apply a fill to any closed boundary. Placing many fills in a document can significantly increase the size of the document. A single fill can be used for the symbol by filling an area that represents the outer edges of the symbol and displaying the detailed graphic linework on top of the fill. The blank color can be used with any graphic object besides fill, so experiment and you might find other uses for this masking capability.
For objects with blank color exported to .dwg and .dgn file formats, the object might be printed. SmartSketch translates the color of blank entities to the background color of the foreign application. Although the objects do not display on the screen, they could be visible on printouts, depending on how the foreign application handles objects with a background color.
To use this functionality, you must install the Symbol Authoring option.