Build Flash or Java Based App for Web View: 3D Blocks Model

Creating application to be embedded in webpage. Application is 3D "blocks" model with nice interface, graphics and tool icons. Purpose of application is to help user to put blocks representing a modular structure. User will put blocks of certain sizes, put it in a platform of customizable size (as land area). There are few block sizes, each will be labeled to a certain name and have certain specs, also configuration info. User can rotate the blocks to find the desired layout. User can add remove replace blocks. There are calculations of area used, total living area, estimated cost, and other useful numbers provided for users based on their layout and amount of blocks (housing module) used. Other supporting feature (support user experience) Initially, there are 4 box types/sizes/spec, and there's option to add more box types/sizes in the future. Application as light as possible for loading time, but also considering graphic smooth and intuitive ux. In this atachment video, I am using sketch up to show basic idea of the application. Application that mimic similar intention: [login to view URL] >> too much [login to view URL] >> almost there, but feels sluggish, low ux