Hi @ashwinash112,
When you create an assembly, do the objects/families contain reference planes?
Some time ago i found out that the viewport size of assembly views (based on boundingbox) is heavily affected by reference planes inside the objects/families. Very strange, it would seem much more logical to me if the boundinbox would only fit the actual geometry of the objects/families.
If it is a “bug” it is probably more a Revit than a Dynamo thing.
Kind regards,
Mark