Created by the developers of PaintCode, this infographic offers a wonderful explanation of how rendering and screen sizes are handled with the new iPhone 6. Although the iPhone 6 has the same aspect ratio as the iPhone 5, it introduces some new behaviors such as @3x scale modifiers in image filenames and pixel downsampling. This infographic demonstrates the flow from the points you use in your code (the abstract coordinates) to rendered pixels (after applying @2x, @3x etc.) to physical pixels (what get rendered on the physical screen, possibly after downsampling on iPhone 6 Plus).
One of the difficulties in building a 3D game is coming up with visually appealing 3D models. Even at the prototype stage, using attractive 3D models can really help promote your game and keep you motivated to keep working on your game. I'm not a good 3D modeler myself, so I was thrilled to find Yobi3D, a "search engine" for 3D models - simply type in a search term and you'll be shown a list of 3D models, with live 3D previews in your browser. I searched for "cat", "dragon", "car", "castle", even "beer" (hey, it is Friday after all 🍺) and got some great 3D models for each. Give it a shot and let me know what interesting models you find.