I am a UDK developer and I really love Unreal technology.
Recently, however, I was asked to develop a browser-based, 3D graphics application. Being browser-based means that I probably can't make it with UDK. So, I'd like to know which alternatives are available.
Basically, said application would consist on 3D replicas of buildings, which the user would then be able to walk around/visit (almost like a FPS game).
On top of that, the user should be able to purchase/order goods from within this "game"/simulation. I'm talking about real life goods, not in-game goods (basically, there would be an online store inside this small 3D world - think Amazon, but way smaller).
Mind you, this would be "singleplayer" - it isn't supposed to have multiplayer interaction.
What I'd like to know is, what are the best tools/software for this kind of project? Which game engine would be the most adequate and stable for this? Maybe Unity? Or even a reliable webgl game engine (if there is one)?
Also, I've never developed an online store... do you know any good resources/tutorials? What kind of available tools are there to "process" the money/cash flow? It kinda confuses me, I mean, working with credit cards and stuff like that... I heard PayPal's API is easy to use, is it? How about transactions made with smartphones, what tools are there for that?