PowerView is a component in the PowerBI suit of analysis tools that are available with SQL Server and Office. . Dynamics AX includes a set of cubes as a data source that can be used with PowerView. From the AX2012 R2 release there was some enhancement done to make it a little easier for the user to go from the application client or enterprise portal to get to PowerView to do ad-hoc analysis.
This is a quick overview of some of those capabilities.
If you want to read more about the technology behind this you can do a search on ms.com. One example article
If you want to get an all up view of PowerBI you can start here
This video was recorded with AX2012 R2 and the same features are in AX2012 R3. If you have prior versions you could still use PowerBI with the cubes that are supplied with Dynamics AX but you just wouldn’t have the “Analyze data” button that you see in different list pages and forms in AX.