The skill to quickly view a object from a particular angle and distance, is a most important skill in building. It is not just useful in building, but gives you much power when playing Second Life, allowing you even to view past walls and hunderds meters away. To be a expert builder, you must master camera navigation throughly.
The Focus button lets you view a object from various angles. Note that you can invoke the Focus mode by simply holding down the Alt key. (or Option on the Mac). You do not need to bring this build dialogue up.
In Second Life, what you see on the screen, came from what's called a camera. This camera has a position, direction, and orientation. The camera is normally at 1 meter above your head and 3 meters behind, and it faces forward, with a orientation that's the same as your upgright body. So that, you constantly see part of your head and shoulders from the back, and scenes in front of you.
When you are in Mouse Look Mode, the camera is positioned in your head. (scroll mouse wheel to move in/out of Mouse Look mode, or pressy “m”.)
Second Life allows you to change the position and direction of the camera freely, independent of your avatar. If you are skilled, you can manipulate the camera as to follow a path, allowing you to view into corridors. In effect, it's like you have a remote controlled floating camera that you can send to snoop things while you standstill.
Here are descriptions on how to control your camera. These techniques can be used while building too:
• To zoom in/out: hold down Alt, then click (and hold) on the object of interest, then move your mouse forward/backward.
• To orbit your camera left/right around a object: hold down Alt, click (and hold) on the object of interest, then move your mouse left/right.
• To orbit your camera up/down around the object: hold down Alt and Ctrl, then click (and hold) on a object of interest, then move your mouse up/down.
• To pan the screen (meaning: moving your camera down/up/left/right but without rotating your camera): hold down Alt and Ctrl and Shift, then click (and hold) anywhere on the screen, then move your mouse down/up/left/right.
The camera can also be controlled using just the mouse. Select the menu 〖View ▸ Camera Controls〗 and you'll get a user interface pane.