I’ve used the mapper in Rhino to create a new Revit family from a Rhino block. When I then try to stream the blocks from Rhino into Revit, they show up in the correct location relative to the survey point in Revit, but the scale is not correct.
The block in Rhino has a height of 381 inches, but it is received in Revit as 381 feet. The units of both models are the same, and the received geometry appears in the correct location relative to the Survey point.
If you copy a block from a document that has different units set or change the units in your current document after creating blocks in a different unit, this issue may arise. For example:
Let’s say you modelled a block in a document where project unit is meters. You change the document units to millimeters. What rhino will do is it will scale the block instances by 1000, but the geometry would remain modeled as if it were in meters. (same for copying blocks from other documents) Hence it will look much bigger/smaller when received in Revit.
To resolve this, you can try exploding the blocks and recreating them in active document or changing the document units accordingly.
Thank you so much for the guidance. When I used BlockResetScale on the block instances, it showed that they were indeed 12x the correct size, which indicates, as you mentioned that the units of the original block model were different than the active model, and they were scaled when brought into the active model. As you suggested, I edited one instance of the block in the active document, scaling it about its basepoint, and then reset the scale of all of the other instances. When I mapped these to a new Revit family instance, they came into Revit at the correct scale. Thank you!