Tutorials

Map artwork to 3D surfaces with Illustrator CS2

by Mordy Golding

One of the things that really sets the 3D effect in Adobe® Illustrator® apart from the 3D features found in other vector applications is the ability to map 2D artwork onto the surface of a 3D object. This method of combining 2D and 3D graphics is called artwork mapping.

So that you understand what artwork mapping really is, let’s take a closer look at a 3D cube. A 3D cube has six surfaces. Each of these surfaces is treated as a separate entity, and artwork mapping is the process of placing artwork onto these surfaces (Figure 1).

Figure 1: Starting with a normal square, a 3D Extrude effect produces a cube with six surfaces. When 2D artwork is placed onto these surfaces, the result is a 3D object with artwork mapping.

There are a few things you have to know before you get started with artwork mapping:

• Artwork must first be defined as a symbol before it can be mapped to a 3D surface. This is actually pretty cool because as you modify a symbol, you will see it automatically update on any 3D surfaces.
• You can’t map a single symbol across multiple surfaces of a 3D object. If your 3D object has multiple surfaces, you can map symbols to each side individually (Figure 2).

Figure 2: In order to create the appearance of artwork that wraps around multiple sides of an object, you have to create multiple symbols and map each section separately.

• When rendering a 3D object, Illustrator uses corner anchor points to define a new surface. Smooth anchor points will not define a new surface. When drawing your art, carefully specifying where corner or smooth anchor points appear on your path gives you greater control over how many surfaces are created and where they appear (Figure 3).

Figure 3: By using corner anchor points at certain points on the path of this profile of a wine bottle, you can specify several surface areas to which you can map art.

• Stroked objects make things more complicated. Objects with fills and strokes applied result in an object that has many more surfaces, which makes it difficult to work with. When you’re creating a 3D object that will have artwork mapped to it, it’s best to avoid using stroked paths.
• Although the 3D effect in Illustrator produces vector results, there are certain times when the 3D effect has to rasterize mapped artwork. If your mapped artwork contains gradients or raster images (such as those placed from Adobe Photoshop®), Illustrator renders them at the resolution that is set in the Document Raster Effects Settings dialog. Even if your mapped art contains a high-resolution Photoshop file, Illustrator resamples it to match the resolution set in the Document Raster Effects Settings dialog. For best results, make sure the resolution setting in this dialog is high enough for your output needs.

Specify mapped artwork

In order to map artwork onto the surface of a 3D object, you must first apply a 3D effect to an object. Then, from either the 3D Extrude & Bevel Options dialog or the 3D Revolve Options dialog, click the Map Art button to bring up the Map Art dialog (Figure 4). If the Preview option in the resulting Map Art dialog isn’t checked, go ahead and turn it on so that you can see what your mapped artwork will look like as you make adjustments to it.

Figure 4: The Map Art button appears directly below the Cancel button in the 3D Revolve or 3D Extrude & Bevel Options dialog.

Before you can map art onto your object, you have to choose onto which surface of the object you want to place your artwork. At the top of the Map Art dialog, there are buttons with arrows that allow you to navigate or step through each of the surfaces of your object. As you step through each surface, Illustrator displays the selected surface in the center of the Map Art dialog. In addition, Illustrator tries to help you identify the selected surface by highlighting it with a red outline on the artboard (Figure 5). Depending on the color of your object, this red outline could be helpful, or it could be barely visible.

Figure 5: Illustrator tries to help you identify each of the surfaces, although the alignment of the red outlines isn’t always perfect on the artboard.

The surface that appears in the Map Art dialog is shaped as if it is laid flat. You’ll notice as you step through the different surfaces on your object that some show a light gray background whereas others show a dark gray background. Some surfaces may even show a background that is dark gray only in certain areas. This is Illustrator’s way of letting you know which surfaces, or which parts of a surface, are not visible, or are hidden from view (Figure 6). As you would expect, if you choose to use the track cube to view your object from a different perspective, the shaded surface areas in the Map Art dialog updates accordingly.

Figure 6: This surface, which is the section that connects the body and neck of the wine bottle, has both shaded and non-shaded sections.

Once you’ve chosen the surface you want to map art onto, use the Symbol pop-up menu to choose a symbol. The selected symbol appears on the surface area in the Map Art dialog with a bounding box. You can drag the symbol to position it to your liking on the surface, and you can also drag on the handles to resize it (Figure 7). As you adjust the position of the symbol, you will see the preview update on the actual 3D object on the artboard. Alternatively, you can use the Scale to Fit button at the bottom of the Map Art dialog to have Illustrator resize your symbol to fit to the surface, although it does so non-proportionally.

Figure 7: You can move and rotate a symbol so that it appears as you need it to on the surface of the object.

Once you’re happy with the size and position of your symbol on the selected surface, use the arrows at the top of the dialog to navigate to another side to map additional symbols, as needed. At any time, you can click the Clear button to remove a symbol from a selected surface, or you can click the Clear All button to remove symbols from all surfaces at once. By default, Illustrator only calculates shading and lighting for the actual surface of a 3D object, and not artwork that is mapped to a 3D surface. Illustrator does this purely for performance reasons. We mentioned earlier that Illustrator uses blends to calculate shading, and breaking down intricately mapped artwork and shading each element with blends takes quite a bit of processing. However, in order to get a realistic appearance, most likely you will want your mapped artwork to be shaded, even if it takes a bit longer to do so. Checking the Shade Artwork (slower) check box forces Illustrator to shade both the surface of your object and the mapped artwork as well. This setting applies to the entire object, and you don’t need to turn it on for each individual surface.

Tip: It’s easier if you create your symbols at the correct size before you map them to a surface; this way, you won’t have to worry about getting just the right size or position in the Map Art dialog.

Note: A surface can contain only one symbol. If you want multiple art items to appear on a single surface, you have to define a single symbol with all of the elements in it.

The last setting in the Map Art dialog is a check box marked Invisible Geometry, which is a slightly technical term. When this option is turned on, Illustrator hides the actual 3D object on your artboard and displays just the mapped artwork. The result is a symbol that appears to float in space. A good example of when this setting might be useful is when you want to make text appear as if it were wrapped around a sphere (Figure 8). When you’re happy with your artwork mapping settings, click OK to accept the settings in the Map Art dialog and then click OK to close the 3D dialog.

Figure 8: You can map artwork around a sphere (left), and by using the Invisible Geometry option in the Map Art dialog, you can hide the sphere leaving just the artwork (right).