Drawing in 3D on a 2D Screen with SketchUp’s Drawing Axes
The drawing axes are the key to understanding how SketchUp works. Simply put, you use SketchUp’s drawing axes to figure out where you are and where you want to go in 3D space. When you’re working with the color axes, you need to keep three important things in mind:
The red, green, and blue drawing axes define 3D space in your model. If you were standing at the spot where all three axes meet — the axis origin — the blue axis would run vertically, passing through your head and feet.
The red and green axes define the ground plane in SketchUp; you’d be standing on top of them. The axes are all at right angles to one another, and extend to infinity from the origin.
When you draw, move, or copy something parallel to one of the colored axes, you’re working in that color’s direction. If you’re drawing a line parallel to the red axis, you would be drawing “in the red direction.”
You can be sure that the line you’re drawing is parallel to the red axis because the line turns red to let you know. If you’re moving a box parallel to the blue axis, you’re “moving in the blue direction.” You know you’re parallel to the blue axis because a dotted, blue line appears to tell you so.
The whole point of using the red, green, and blue axes is to let SketchUp know what you mean. Remember that the big problem with modeling in 3D on a computer is the fact that you’re working on a 2D screen.
If you click the cylinder with the Move tool and move your cursor up, how is SketchUp supposed to know whether you mean to move it up in space (above the ground) or back in space?
That’s where the colored axes come into play: If you want to move it up, go in the blue direction. If you want to move it back, follow the green direction (because the green axis happens to run from the front to the back of your screen).
When you work in SketchUp, you use the colored drawing axes all the time. They’re not just handy; they’re what make SketchUp work. Having colored axes (instead of ones labeled x, y, and z) lets you draw in 3D space without typing commands to tell your computer where you want to draw.
They make modeling in SketchUp quick, accurate, and relatively intuitive. All you have to do is make sure that you’re working in your intended color direction as you model by lining things up with the axes and watching the screen tips that tell you what direction you’re working in. After your first couple hours with the software, paying attention to the colors becomes second nature.