No brep for a model

I have a 3d step file with round 7000 surfaces (it shows while laoding the model). Its Geometry type is
Rhino.Geometry.InstanceReferenceGeometry. I am unable to convert the model to brep. How do I do edit operations on surfaces through code for such a body?

Hi Rushank -

When Rhino reads a step file, the objects will generally be inserted as (nested) block instances.

In Rhino, you’d use ExplodeBlock.