There are six default layers. Layer names use uppercase alphanumeric characters and underscores. When you add an object to a design, it is assigned to a default layer according to object type.

In legacy designs, the default layers are mapped as follows:

All graphic elements in a design can be assigned to a specific layer. The elements include blocks, lines, fibers, text, labels, groups, ports and highways.

You can also configure layer properties that will effect all objects on a layer.

When you export a design sheet with cross-sheet fibers and then import the sheet, the cross-sheet fibers are partially imported. To prevent modification of a partially imported fiber, it is automatically placed on the default, protected layer PARTIALLY_IMPORTED_FIBERS. When you import the sheet to the design it was exported from, and it includes the other end of the cross-sheet fiber, the imported fiber is placed on its original layer.