Having had many projects such as yours…to ultimately be distributed via mobile phones I can tell you that a single optimization stragey is not going to get you where you need to go. To get your project to be viable on a mobile phone you will have to re-topologize your geometry and use atlas maps, map packing, and every other optimization technique at your disposal. You will be faced with a series of hurdles you will have to overcome. The first is the delivery size… this is the total size of all the files that has to be downloaded by the mobile phone. This has to be relatively small as you have already found out. Mobile devices will time out much faster than a desktop/laptop. So the number of files and sizes of the files have to be limited. The second hurdle is performance once loaded on the mobile device. Here you will be faced with reduced processing power and your optimization will be geared towards solving user interaction and the users ability to use your app. This is where the atlas maps and map packing, will play a big role. one 4096×4096 containing 256 maps…is far fewer redraws than 256 individual maps. Depending on your maps this will be something you need to evaluate the download size vs redraw performance and decide which is better.
But you need to concentrate on the model at the moment..getting that total triangle count under 500,000. Even lower if you are using lights.
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