Bridge Family with parameters

I am new revit user and trying to create Revit family for Box Girder Deck - two cells (Inconstant Height) with parameters. If I change any parameters, it showing error, please find the attached family.

Please help me out thisBOX-2-CELL.rfa (484 KB)

Missing the attachment. Also I’m not sure how Dynamo applies here - likely you’re better off asking in a Revit forum.

You should use the Generic Model Adaptive Family template. Reference points will be the key factor when generating the changing section geometry of your girder.