1. Moving to the left by setting translation to -0.5
2. Moving to the left by setting location to -0.5
In the first case you can see the image shift within the sphere which it does not do in the second case. It’s a little confusing to visualize what’s happening here and that makes it hard to describe. Anyway, here’s a try at it and the nest video may also help:
When you move the ball to the side using the Translation value, the image is changed as if you stay in one place while the ball moves straight sidewise. Therefore, your perspective changes and you see more of the inside aspect and less of the part toward the outside of the window. If you move it using the Center coordinates on the Location Tab, it’s as if you move along with the ball, leaving your perspective unchanged.
I took a while to answer because I wanted to check things out a little more thoroughly beforehand. I sometimes only open my mouth to change feet and the fact that it’s a frequent occurrence doesn’t make it any more acceptable.
As far as I can figure out, once you have transferred the coordinates, magnification and rotation to the Mapping Tab and reset the values on the Location Tab, it doesn’t really matter if you use Center Coordinates on the Location Tab to reposition the image.
I checked it out using another image with high magnification and didn’t find any surprises. The one thing I have not yet done is look at a two-layer image with different magnification values and rotations to see if both methods of re-positioning yield the same results. I *know* that you can map “unlike” layers using the Mapping Tab with predictable results and I don’t know that for sure using the Location Tab.
If you use the Mapping Tab, it is a simple matter to use the Rotation input boxes to rotate the image slightly as desired. The spiral in the image I’ve attached makes it fairly easy to follow what happens. Change the values in the Rotation boxes and watch the results. Remember that the basic image has been rotated 42 degrees so the movement won’t be quite “square” to the screen.
For added effect, I added Glass Hemisphere to the lower layer, made the area around the sphere transparent and used an alpha channel to render most of the spiral image transparent as well. Have fun!