To change the bounding box scale
If the estimated bounding box scale is too small, a warning message appears in the render log with instructions on how to set the bounding box scale correctly. An example message:
Warning: The bounding box is too small for shape “surbsSphereShape1”. Reset the bounding box scale to: 1.56778 1.56778 1.56778. You can use the following mel commands: setAttr nurbsSphereShape1.boundingBoxScale -type double3 1.56778 1.56778 1.56778;