OrthoGridZup
Representing and visualizing 3-dimensional objects in a 2-dimensional drawing is difficult. This applet is to help 'see' things in 3-dimensions(3D) from 2-dimensional representations.
The panel on the right shows a point A where you can rotate the view and move the point. Selecting the point shows either cross arrows where you can move the point parallel to the xy plane or opposite arrows where you can move the point parallel to the z-axis. The coordinate position shows the x, y and z values for the location.
There are several methods for represensting 3-dimensional objects in a 2-dimensional drawing. This applet illustrates an orthographic projection with the z-axis upward. Other representaions are oblique, perspective and 3D glasses. Oblique projection has a cartesion 2D grid with out of plane locations shifted at an angle. Perspective projections have objects further away drawn smaller. This is typically what is used in computer games because it is the most realistic for larger spaces. 3D glasses give a different image for each eye. This is how people can tell distances in the real world.
The initial 3D view and left pannel shows an orthographic projection where the z axis is up.
As you move away from the origin O in the x direction move down 30^o from the right. Moving in the y direction moves 30^o up from right. Movind in the z direction moves up.
Selecting "Show Components" will shows vectors allong each axis representing the coordinate components. Selecting "Show Path" will show a path from the origin at the point A moving first in the x-direction then the y-direction and finally the z-direction.
For this activity move the point A in the right 3D view. Change the view mode. Rotate the view. Try to get a feel for orthographic projects.
Note there is some inconsistancy because the initial point in the left panel A=(3,2,2) with each grid line being 1/2 unit. The point A=(3,2,2) as shown on the left panel could be (2.5,2,0), (2.5,0,2), (1/2,2,0) or (0,2.5,-.5).