Just to add to this comment. The SAP Software Use (attached) manual contains the following clause under the section for SAP HANA DB Edition for SAP Netweaver BW:
"Use of the SAP HANA Studio component is limited solely to the administering, monitoring and creating custom views for the SAP BW instance. All reporting must be performed via the SAP BW software or via custom views created using HANA Studio. Such custom views may be access via SAP or non-SAP BI tools."
My reading of this clause leads me to the conclusion that you may create your own custom analytical and/or calculation views on the BW Database tables and use non-SAP BI tools to consume these views. However, please defer to your SAP account executive for formal clarification on specific software use under your license agreement.