Anim8or - Basics to Advanced/User Interface Overview/Object Edit
The first button we will go over is the arrow button all the way at the top of the toolbar:
This button puts you in Object/Edit mode. There is also an arrow button below this one. Don't confuse the two. The top one puts you in the Object/Edit mode while the other one is the Select button.
your 3D objects. When you are in this mode you can zoom in the view, move around
the camera, and also rotate the camera.
The button below the Object/Edit button is the Object/Axis mode.
Object/Axis mode will allow you to move the XYZ arrow so an object will rotate about itself. First select the problem object in top menu under OBJECT, select its name (if you haven't named it, will likely be something like object01, object02 etc.). Now the object will be isolated. You must be in WIREFRAME view mode to see the red and blue arrows. Click the object/axis button, then immediately click the move tool below it and you will now be able to drag the blue and red arrows to the center of your object. Don't move your object when moving the red and blue arrows for your pivot point, you will see in the very center of the grid (turn on grid ) very large red and blue arrows. Your object will located on the grid where it is supposed to be in relation to other objects (in the world) so it wont be centered on master grid. OKAY, back to moving your arrows: With the MOVE TOOL selected - Move the XYZ arrow into the center of your object then choose LEFT VIEW so you can see it from the side and move the XYZ arrow center once again to the center. Use the ARCH ROTATION viewing gizmo as well to immediately rotate your view in all directions to be sure XYZ arrow is dead center of object. To get back to a dead on straight view, exit the arch gizmo and choose from the TOP MENU bar "VIEW" and then choose "FRONT". Save often your work often. ((CAREFUL! Each time you change the VIEW to center your XYZ arrow, you must AGAIN select the object axis button and then move tool, or you might move your object if you don't pay attention.))
If you were having trouble with an object darting off screen each time you attempted to scale, this will likely solve that problem as now the pivot point (arrows) is within the object. It is desirable in most of your pieces, to have an object pivot in place - especially when building up items - as this will allow you to rotate and scale an object so it fits onto another without the object arching off into the distance. In other cases, you might wish to have the pivot/axis point in another spot on the object. If you had a foot, you might want to move to pivot closer to the ankle, so the foot would rotate around the ankle area, as in real anatomy (Im NOT talking about bone/figure mode). Or if you have a door, the pivot could be moved to the edge where hinges are normally, and the rotation would be real world physics correct. Pivot/axis points are a concern when you are turning objects around to see them and move/attach them.
Later in your 3D project the pivot/axis point will be important to you if you animate that object across a timeline in a movie. Again, a leg should rotate at the hip socket, hands of a clock would need to rotate from the end where they attach to the center, etc. Those old action figure GI JOE dolls with the ball joints, where you can bend the legs, arms, neck... that's a good way to think of pivot points. There are even quite a few action doll animations on Youtube where people animate the figures to look alive. Same concept in your 3D world.
Lastly, keep in mind that, for example, a toe might have its own axis/pivot—but once you JOIN SOLIDS and attach the toe to the foot—you are now dealing with the pivot/axis of the foot. The toe has been absorbed by the foot as far as pivot/axis is concerned.
The button immediately to the right of the Object/Axis button is the Object/Point Edit mode button:
This button puts you in a mode that allows you to edit the properties of the 3D object's vertices, faces, and edges.
Right below those buttons are the Screen Coordinates option buttons:
With these buttons, you change which type of coordinate system you want the program to go by. Options are world, object and screen.