Microsoft has released a preview of the Azure Analysis Services web designer.  This is a browser-based experience that will allow developers to start creating and managing Azure Analysis Services (AAS) semantic models quickly and easily.  SQL Server Data Tools (SSDT) and SQL Server Management Studio (SSMS) will still be the primary tools for development, but this new designer gives you another option for creating a new model or to do things such as adding a new measure to a development or production AAS model.

A highly requested feature is that you can import a Power BI Desktop file (.pbix) into an Analysis Services database.  And once imported you can reverse engineer to Visual Studio.  Note for PBIX import only Azure SQL Database, Azure SQL Data warehouse, Oracle, and Teradata are supported at this time and Direct Query models are not yet supported for import (Microsoft will be adding new connection types for import every month).

This initial release includes three major capabilities, model creation, model editing, and doing queries.  The model can be created directly from Azure SQL Database or SQL Data Warehouse or as mentioned imported from Power BI Desktop PBIX files.  When creating from a database, you can choose which tables to include and the tool will create a DirectQuery model to your data source (DirectQuery is where the query to obtain the model is passed down into the data source and executed there).  Then you can view the model metadata, edit the Tabular Model Scripting Language (TMSL) JSON, and add measures.  There are shortcuts to open a model in Power BI Desktop, Excel, or open a Visual Studio project which is created from the model on the fly.  You can also create simple queries against the model to see the data or test out a new measure without having to use SSMS.

Keep in mind that if you save changes to the TMSL, it is updating the model in the cloud.  It is a best practice to make changes to a development server and propagate changes to production with a tool such as BISM Normalizer.

More info:

Introducing the Azure Analysis Services web designer

Azure Analysis Services Web Designer