Join Deke McClelland for an in-depth discussion in this video 3D explained: XYZ position and orientation, part of Photoshop CS5 Extended One-on-One: 3D Fundamentals.
In this exercise I am going to introduce you to the X, Y and Z axes, which define 3D space inside Photoshop, and give you a sense of how you might work with the position and orientation options. Now this gets a little bit technical, I'll warn you up front, because we're talking about spatial design, and some of you are going to get it and some of you not so much. I don't expect anyone to completely take it in and remember every bit of information here. It's just a way of giving you a sense of what's going on in the world of 3D inside Photoshop.
So here we have the chair which Photoshop has chosen to import on its back and I've gone ahead and called this file Poor chair.psd. Now I am going to switch to the Camera tool which is located directly above the Hand tool inside the toolbox and specifically you want to make sure if you're working along with me that you have the 3D Rotate Camera tool selected. Also, notice up here in the Options bar that the View is set to Default. The Default camera angle is always in place for every new 3D layer you create inside of Photoshop. That said, you can override it using this tool anytime you like.
To get a sense of what that ground plane looks like, let's go ahead and go to the View menu chose Show and then choose 3D Ground Plane. Notice what's going on here. The X-axis is red, the Y-axis is green, the Z-axis is blue. Well, we are not seeing the blue axis, because the Z-axis is perpendicular to the ground plane. The ground plane itself is ultimately a 2-D plane like the ground and therefore it is defined by just two axes, X and Y. The strange thing is that with Photoshop's Default view that Y defines the horizon and X defines depth, which is different than most programs.
Of course you can override that any time you want using this tool, just by dragging around inside the image window and then I could go ahead and set that red X-axis along the horizon and now the Y-axis defines depth. That still doesn't explain, however, why the chair is on its back. We need to modify that chair. So how in the world do we do that with some degree of accuracy? Well, let me show you what's going on inside this diagram, which I call Photoshop 3D geometry.psd. I am going to go ahead and turn off that ground axis now by going to View menu, choosing Show, and choosing Ground Plane. And then I am going to turn on a layer group here inside the Layers panel.
It's called the axes, this folder right there, and we see not only each one of these axes as it is angled according to the default camera, but we also see the direction of positive movement. So for example, with the sphere layer active here I'll go ahead and select from this tool slot either the 3D Object Pan tool or the 3D Object Slide tool. Either one will do. I'll go ahead and select Pan for now. Then you can change any of these three position values. So if I change the X value to let's say 50 and press the Enter key or the Return key on the Mac, quite strangely the object moves away from us.
Again that's just subject to the default camera angle, nothing more. We can always change that but that is the direction in which we are going to move that object. All right, I'll press the Escape key and then press Ctrl+Z, Command+Z on the Mac. Esapec of course in order to interrupt that rendering. All right, now let's change the Y value to 50 and watch it moves in the direction of this line, which is to say by default to the left. All right, I am going to press the Escape key and then press Ctrl+Z, Command+Z on the Mac in order to reinstate that sphere. Now let's change the Z value to something not quite as big, because otherwise the sphere is going to leap off the screen.
I'll change this value to 25 and notice that goes ahead and moves this sphere upward, which is what we would naturally expect I think, in the direction once again of those arrows in the diagram. I'll go ahead and press the Escape key and press Ctrl+Z, Command+Z on the Mac to undo that movement. Now for orientation, which might be the part that really makes your brain hurt here. But it's the information we need in order to pick up that chair. So we've got this sphere that's mostly covered with black-and-white checks but then we have some yellow and purple checks down here at the bottom and that'll help us track orientation.
In order to get to the numerical orientation values, I need to switch to either the Rotate tool or the Roll tool and I'll switch to the Roll tool for now. All right, now for the Orientation options, which are the ones that are most likely to make your brain hurt but they're also the ones that we need to use in order to pick up that chair. Here inside the Layers panel I have another group called 3-D rotations. This is what it looks like when I turn it on. Each one of these curving lines represents the direction of a positive rotation value, either X, Y or Z. So red is X, green is Y, and then blue is Z and in each case we are rotating around the corresponding axes.
So it happens to be if the axis is declining away from us, a positive X value applies a counterclockwise rotation, a positive Y value applies a clockwise rotation, and then a positive Z value another counterclockwise rotation. Again, I do not expect you to remember that but that is the way it works. To see it in practice let's go ahead and switch to one of these two tools here, either the Rotate tool or the Roll tool. I'll go ahead and click Roll and that gives us access to the Orientation values, and I will enter an X value of 90 degrees and press the Enter key or the Return key on the Mac, and sure enough we are rotating the sphere in a counterclockwise direction, which is why what was formerly the bottom of the sphere moves up into the right.
Now what I'd love to be able to tell you is we could just keep a bunch of different rotation values on top of each other. But if you start doing that, it gets confusing. Because as soon as I rotated that sphere up into to the right I swap the angle of the Y and Z axes. It may be a little difficult to understand, but that's what just happened. So when you're applying these kinds of rotations numerically you typically only want to modify one or two axes of orientation. So for example if I want to get a sense of what's going on with Y and Z, I should undo X by pressing Ctrl+Z, Command+Z on a Mac.
Then let's change the Y value to 90e and we'll see it move up and toward us in accordance with the direction of that green arrow right there. Now as I say, we can go ahead and combine two rotation values with each other and still make sense of it. So I'll press the Escape key to stop the render and I'll change the Z value to 90 degrees as well and as soon as I apply it, we're going to rotate that sphere in a direction of the blue arrow, so what was formerly the front part of the sphere becomes the left side. All right, so that's all very well and good.
How do we take this very and apply it to the task at tipping the chair upright? I will explain exactly how in the next exercise.
- Creating basic 3D shapes
- Converting 2D art to 3D
- Using the Camera Rotate tool
- Cutting holes from shapes
- Rotating and positioning by the numbers
- Importing a model from Google SketchUp
- Assigning materials and lights
- Setting orientation and position
- Designing a custom bump map
- Modifying the attributes of a material
- Adding a person to a 3D scene