First time I used Unreal Engine 4(Game engine) for my professional task. It was a huge game changer!!! Client overseas was able to see the whole scene of tens of houses, thousands of trees, many people, cars real-time live, through Skype and we worked together on designs of houses from sketches, on details.
Needless to say, that client was so much satisfied and amazed with such opportunity. No waiting for pre-renders, stages, etc. client actually could see the whole process and take part in it. I was also pleased with the process, as I would concentrate on the actual scene without making a lot of images from stages for corrections/approval.
After Scene was ready, we choose 40 positions of shots and those were generated in seconds each in high resolution already post-processed. This completed scene also makes possible to make fly-trough animations in no time compared to the typical way of rendering. So it means that cost a lot cheaper for the client and the result is decent. Of course, particular images are far from photorealism and perfection, which could be achieved with greater budget/time. But it can be even better.
So contact me, if You want great, interactive, streaming result faster despite of scale of a project!