US Army Modeling, Simulation, and Training (MS&T) is moving toward cloud based solutions to meet the future training needs of the Warfighter. Cloud based solutions will need to provide easily accessible synthetic training tools that will enable soldiers all over the world to train together. The Army is investing in cloud technologies and leveraging research to provide Point of Need (PoN) training services and reduce the cost of deployment and sustainment. This paper captures the lessons learned from a government funded effort to develop an open source light weight cloud based 3D visualization tool for MS&T applications. In addition to looking at broader applications, our effort is specifically targeting needs of the Army's Live Virtual Constructive – Integration and Architecture (LVC-IA) program as a transition target. Our work has resulted in a thin client 3D viewer that runs in a browser and leverages common US Army standards and components for exercise data, terrain, and model data. We will discuss how open solutions and leveraging new government developed technologies can provide a cost-effective solution while still achieving commonality and interoperability. We will discuss the approaches used, such as streaming terrain elevation data, ground surface imagery, and 3D models from cloud based servers to thin client 3D viewers and examine different technologies for rendering a 3D scene in a web browser. We discuss the practical challenges of transitioning this technology to meet cloud requirements of LVC-IA and other Programs of Record. Lessons learned will be presented regarding implementation and fielding of a web based solution into a large, complex training environment.