[V8i SS3 MDL] Migration from V7 to V8iSS3 : how to know if I am in 3D

Question

Hello everybody, 
 Once again I don't know how to 'translate' a piece of V7 code. 
 I have : 
 if ( (tcb -> fbfdcn.design3d == 0)) { mdlInput_sendKeyin ("ACTE2D SECTION2D BACKDGN_RETOUR", 0, INPUTQ_EOQ, ustnTaskId); return INPUT_COMMAND_REJECT; } 
 'design3d' is no more an element of the fbfdcn struct. 
 How could I replace that piece of code in V8iSS3 ? 
 Can anybody tell me where can I find documentation on V7 MDL ? 
 Thanks, Pascal.

Jon Summers · Accepted Answer

Unknown said: 'design3d' is no more an element of the fbfdcn struct 
 MicroStation V7 stored graphic elements in a DGN design file. The file could be 2D or 3D. That TCB variable tells us that dimension. 
 MicroStation V8 stores multiple models per DGN file. Each model may be 2D or 3D. A file therefore has no dimensionality. You must examine each model to determine whether it is 2D or 3D. 
 MDL's API to DGN models is the mdlModelRef_api. mdlModelRef_getActive returns a pointer to the active model. mdlModelRef_is3D tells you if a model is 3D or 2D. 
 Unknown said: Can anybody tell me where can I find documentation on V7 MDL? 
 Perhaps the Bentley Systems website?