Photoshop  CS4 Extended - Movement on a 3D Layer
© 2009 Robin Wood
This is the third movie in this tutorial. If you’ve been following along, you've already opened the model, and it’s lit. If you don’t know how to do those things, please watch the previous movies.
Once you have the mesh lit well enough to see, you’ll need to know how to move it around, so that you can reach the areas you want to paint.
First, of course, you can move the whole layer around with the normal Move tool, like this, but that just moves in two dimensions, because it’s treating it like a 2D layer. You won’t get any changes in perspective that way.
You can also actually move the mesh in 3D space.
There are two different sets of 3D Move tools.
One moves the Camera and has a little Camera icon on each tool. You’ll find them here. (I’m using the doubled up tools, because this screen is so small. If you’re using one long tool bar, the Camera tools are under the Mesh tools.)
The other moves the Mesh, and has a little Sphere icon.
For some reason, the shortcuts that come with Photoshop assign N to the Camera movement tools, and K to the Mesh movement. I have no idea why. You’ll either just have to memorize them, or change them.
What’s the difference between the two?
Let me show you.
I’m clicking on the Camera 3D Orbit tool. This will let me orbit the mesh on all 3 axes.
And this is what happens when you rotate around the model with the camera. (You can hold down Option/Alt to switch to the Roll toll when you have the Orbit tool, and vice versa, to straighten the model up, by the way.)
As you can see, the lighting on the model stays constant. Things in shadow are always in shadow, and things in the light remain well lit. You can also see that, depending on the angle, the main light on the model may be yellow, or white.
Okay, let’s undo that.
Now I’m getting the Mesh 3D Rotate tool, which, once again, lets me rotate it on all 3 axes.
This is what it looks like when I rotate the mesh.
As you can see, the lights remain in the same position relative to our viewpoint, and the part of the model that's lit changes.
Okay, we'll undo that too.
Here’s another important difference.
I’m going to use the Camera Zoom tool, with this icon that looks like a camera and an eyeball, to zoom in on the model. Now I’ll use the Pan tool to pan up and down.
As you can see, when I drag up, the model moves down. This is because it’s the camera that’s actually moving. If you move a real camera up, the things move down in the view, as well.
Okay, now I’m going to undo all of that. 
I’ll click on the Mesh tools, in the toolbar, and use the Mesh Slide tool to bring the model closer to us.
And now the Drag tool to move it up and down.
As you can see, this time the model moves up when I drag up, and down when I drag down.
So, yeah, there are differences. Which you use depends on which you are more comfortable with.
Personally, I normally move the model. The important thing, though is to remember which one you are using, because of the differences.
If you're moving the model, there’s another interactive tool that will help.
It’s called the 3D Axis. Let me un-minimize it now.
Like most 3D programs, the axes are color coded, with the standard red, green, and blue.
Each axis arrow allows you to do a number of things.
You can drag on the arrow point, like this, to move the mesh along that axis.
You can drag on this little arc section, to rotate the mesh on an axis. See, you get this yellow ring so you can see which way it’s going to go.
And you can drag the box, here, to scale on an axis. (You probably don’t want to do that with this model, though, so let’s undo.)
This white box, in the middle, lets you scale the model proportionally.
In addition, if you move the mouse close to the intersection of two axes, you’ll get a little yellow box that allows movement on those two at the same time, like this.
If the Axis Tool is in the way, you can move it by dragging the gray bar, like this.
Or resize it by dragging this corner. [On the top right]
Or minimize it by clicking here on the left. 
Click right on the minimized icon to restore it.
If you just hate the thing and want it to go away, you can do that in View > Show > 3D axis. And it disappears.
To get it back, of course, enable it again.