Wall by Face from mass generated in Rhino

There are 3 fundamental ways to get Rhino Geometry into Revit.

  1. Direct Shapes
  2. Families
  3. Import/Link .3dm

for your case:

  1. Direct Shape: you can bring in you box as a direct shape categorized as a wall.

  2. System Family: get the line work of the brep base and create by Add Wall By Curve.