I think they are fooling around with you... Neither I or someone else knows what blob type is... But there are more important things than your requesting issue... To make someone use your definitions, you must share them in a file - DWG or hardcoded LSP if you want that that way and you must accept the fact that user(s) have freedom to do what he/she want(s)... No one can guarantee that their work will rely on basis you provided... When, and if, you agree to share, you can't expect that you can get much benefit on either side (you/coworkers)... Success of job done is measured only by pure practical usefulness and you must accept the fact that you can and may be used/misused by your own will - that is the risk everyone takes when acting/lurking or planing events that may or may not occur...