Creating a .CEL File from a DGN File

Question

Hello All; 
 I have a dgn file that contains 5 x 3D design models. 
 Each model contains the logo of various companies. 
 I set up the model so that each model can be placed as a Cell. 
 The issue is this, the dgn file is called Logos.dgn but I have been told that the file needs to have a .cel extension. 
 I have tried to just change the file extension from dgn to cel and every thing seems to be in order but I wanted to ask the community what is any is the correct procedure of taking a .dgn file and converting it to a .cel file. 
 Thank You.

Jon Summers · Accepted Answer

A cell is a model; a model is a cell. A DGN file is a container of models; a cell library is a container of cells. Since cells & models are interchangable, so also are a DGN file and a CELL file. 
 Unknown said: I set up the model so that each model can be placed as a Cell 
 Correct! 
 Unknown said: I have tried to just change the file extension from dgn to cel and every thing seems to be in order 
 As it should be. 
 To make your cell libraries available during a DGN editing session, make sure that your .cel files are located in whatever directories are pointed at by configuration variable MS_CELL . By default, that's ..\Workspace\Standards\Cell\ .