Building 3D Scenes in Photoshop CS6 and CC
Excerpted from 3D Photoshop: Imagine. Model. Create. (Adobe Press)
By Steve Caplin
You can go a long way with modeling, lighting and rendering just one object at a time. But things really start getting interesting when you combine several objects into a single scene. Take the simple example below: the dog is a 3D model downloaded from archive3d.net; the hoop has been created directly in Photoshop by extruding a circular path, revolving it 360° and then expanding the extrusion depth. The trouble is, how do we make the dog jump through the hoop? As two separate objects they can’t interact, even though they’re in the same document, because they’re on two different layers.
The solution is to merge them together so they’re both part of the same layer – and therefore both part of the same 3D scene. Now, we can interact the two models and the dog jumps through the hoop.
Creating and Combining
To explain the process we’ll begin with the wine bottle we worked on earlier, then make a simple hoop and combine the two in a single layer. This will also give us the opportunity to look at object alignment, which becomes critical when working with multiple models.
1 - We made this bottle from a primitive object earlier in the book. I’ve darkened the glass and made the foil cap red. Open this model (shown below), which you’ll find on the 3DPhotoshop.net website.
2 - Make a new layer, then use the Shapes tool set to create paths, and draw a circle. Use the 3D panel to extrude that path, and you’ll see a small, squat cylinder like the one below right.
3 - To turn that cylinder into a hoop, open the Properties panel to the Deform pane, and set the Horizontal Angle (X) to 360° This will produce a tiny, tight hoop with only the default extrusion depth to give it size.
Increase the extrusion depth, either by dragging the slider or by dragging up on the Head-Up Control on the object itself.
4 - We can bring the hoop down over the bottle, even setting its orientation to match the angle of the bottle.
But the one thing we can’t do is poke the bottle through the hoop. The hoop’s layer is in front of the bottle layer, so – just as with any pair of Photoshop layers – the hoop is wholly in front of the bottle.
We can, of course, drag the hoop layer behind the bottle layer, as I’ve done on in the second illustration. But now, as you’d expect, the hoop is entirely behind the bottle.
5 - When we look at the Layers panel, we can see that the hoop and the bottle are two entirely separate layers, and that’s why we can’t get them to interact (well, we could, but only by making a Layer Mask for one or the other of them).
6 - The solution is to select both the bottle and hoop layers in the Layers panel, and merge them together either by choosing Layer > Merge Layers or by using the keyboard shortcut Command-E/Control-E.
As you can see, the two layers have now merged into a single layer, and as standard that layer will take on the name of the lower layer in the selection – in this case, it’s bottle.
It looks as if the two objects have become just one object. But what we’re actually seeing is a single 3D scene, rather than a single object.
7 - When we look at the 3D panel, we can see the bottle and the hoop clearly listed as two separate objects. As part of a single 3D scene, they even cast shadows on one another.
Note that the position of the merged objects will change relative to one another when two 3D layers are merged, often dramatically so. That’s because they started with different ground plane orientations, and when the layers are merged it’s these ground planes that are aligned.
8 - We can select either the hoop or the bottle by clicking on it with the Move tool, or by selecting it in the 3D panel. We can now either use the 3D Axis or just drag on the edges of the bounding box to rotate the hoop around the bottle.
9 - It all looks fine – there’s the hoop still visible behind the bottle. But when we check out the Secondary View, we can see the problem: the hoop is actually passing through the bottle, rather than behind it.
10 - To check what’s going on, we can spin the whole view around, making sure no objects are selected first. When we look from above in the main view, we can clearly see the hoop going through the bottle.
When we’re working normally in Photoshop, this sort of thing doesn’t matter: if it looks right, then it is right. But with 3D scenes we might want to turn the whole scene around to view it from a different angle – and that’s where problems will start to arise. It’s worth taking the time to get it right in the first instance, to avoid potential problems further down the line.
11 - The intersection issue is actually a very easy problem to fix: all we have to do is to move the hoop, using the Secondary View for reference, until it’s centered on the bottle. This view is much more important when working with more than one object in a scene.
12 - Here’s the scene with the intersection problem corrected. It may not look much different to how it appeared in step 8, but the two objects will now behave much more like items in the real world when it comes to refraction, transparency and shadow-casting.
Manipulating Objects in a Scene
1 - As we’ve seen, when two 3D objects are merged into a single layer, both objects now appear as separate items in the 3D panel.
You can manipulate the view of the whole scene by dragging it with the Move tool when no objects are selected. If you want to work on an individual object, there are two ways to select it: either click on the object itself, or click on its folder in the 3D panel.
A selected object is indicated by the bounding box, as well as being highlighted in the panel.
2 - You can pop open an object’s folder to see its contents. This will show the materials used and, if the object is composed of several parts, as this wine bottle is, it will also show all the parts listed as separate meshes within the folder.
To manipulate the entire object, make sure the folder itself is selected, rather than just one of its constituent parts.
3 - As well as selecting the whole object, you can select just a single item within the assembly and manipulate just that on its own. Here, the label mesh has been slid out to one side.
Note how the label is also interacting with the hoop, which now passes through it. All objects within a single scene will interact with each other in exactly the same way.
When you download or otherwise import models, you may well find that they aren’t already neatly sorted into folders. In this case, you’ll often find that when you attempt to move a whole object, you only move one of its parts. Be sure the whole thing is selected first – or place all the parts into a new folder yourself.
4 - A single item within an object group can interact with other objects within that group, as well as with other objects in the same scene.
Here, the bottle cap has been selected, and slid vertically downward. You can see how it has penetrated inside the bottle neck, whose transparency allows it to be clearly visible inside it.
1 - As well as importing objects from a variety of sources, we can duplicate objects within a 3D scene. To do this, select the object in the 3D panel and click on the pop-up menu in the top right: choose Duplicate Object.
2 - When you duplicate an object, the scene won’t look any different. That’s because it will be duplicated directly on top of the original. If you look at the 3D panel, though, you’ll see the duplicate clearly listed below the original.
3 - The duplicated object is an entirely independent model. It can be rotated or scaled, or it can be modified in other ways.
Here I’ve reduced the Extrusion depth of the second ring and then moved it to one side, while leaving everything else alone. This may seem obvious, but duplicated objects behave differently from Instance objects.
4 - Objects can also be deleted from a 3D scene, again using the popup menu in the corner of the 3D panel. Choose Delete Objects from the popup menu list.
Photoshop CS6 Users
If you’re using Photoshop CS6, then the tools listed here won’t apply, as they hadn’t been introduced yet. There’s no simple way to duplicate or delete objects via a menu option.
You can still merge objects together in a single scene, but if you want more than one, here’s the workaround:
- First, duplicate the 3D layer containing the object of which you want multiple copies, once for each copy.
- Select all the layers, and merge them together.
There’s no way to delete an object from a 3D scene in Photoshop CS6. The best you can do is to make it as small as you can and hide it inside another object.
Excerpted from 3D Photoshop: Imagine. Model. Create. by Steve Caplin. Copyright © 2014 Used with permission of Pearson Education, Inc. and Adobe Press.