The current camera switching functionality is definitely quite limited and unintuitive. Cameras *must* be attached to a renderer to be used in the 3D preview. To switch to a camera simply open a renderer attached to it then press View Camera twice. We will be greatly improving the 3D preview and multi-camera functionality in the future which features like a drop-down list of cameras, the ability to create a new camera from the 3D preview, etc.
Currently you can actually accomplish population positioning and the like using a single camera fairly easily. What I do for example is have my set camera position, create a population, then navigate to it with the camera *without pressing the Set Camera button*. I can then move the population and, when I'm done, just press "View Camera" and it takes me right back to the original camera position. An easier alternative is simply to use the 3D preview coordinate readout and enter those values into the population position, which doesn't require any camera movement at all.
- Oshyan