For some external applications (e.g. rendering applications, CNC, calculation programs), it is neccessary to split the DWG drawing into individual layers grouping the same color (e.g. for subsequent assignment of a rendering material), or even to put each drawing entity into its separate layer.
The applications Xanadu Col2Lay and CADstudio Ent2Lay can help in these situations.
Col2Lay processes the selected drawing entities (objects) and moves (separates) all their individual colors (both individually assigned and "ByLayer") into individual layers. It automatically creates layers named by the ACI colors used - "XCL1" to "XCL255". The original (no more used) layers are purged. The drawing blocks are also converted (except the "ByBlock" color, which is not defined globally).
Ent2Lay has a simpler functionality - it moves the selected entities to new, individually defined layers. So each new layer contains a single entity of the original drawing. The layers are named by the type and handle of the original entity - e.g. "XENT_CIRCLE_1E3", "XENT_LINE_385".
Both free applications can be downloaed from www.cadstudio.cz/download.