What’s Behind the Green Door?

Topics Covered in This Illustrator Tutorial:

Compound Paths, the Group Selection Tool

Exercise Preview

Exercise Overview

In this exercise, we'll transform a simple illustration of three doors into an engaging reveal effect by adding circular windows that showcase hidden imagery beneath each door. This technique demonstrates the power of Compound Paths in Illustrator—one of the most versatile yet underutilized features for creating sophisticated cutout effects. Whether you're designing interface mockups, print layouts, or digital illustrations, mastering compound paths will significantly expand your creative toolkit.

1. In the Illustrator Class folder, open the file open-doors.ai.

2. Save as yourname-open-doors.ai to preserve the original file.

3. In the dialog that appears, leave the default options checked and click OK.

Paths Within Paths

Now we'll dive into the core concept: creating shapes that cut through other shapes. Think of compound paths as digital cookie cutters—they allow you to create holes, windows, and complex negative spaces with precision.

1. Select the Ellipse tool .

2. Option–click (Mac) or ALT–click (Windows) in the center of the dark green rectangle in Door 1. This modifier-click technique creates a shape from a specific center point rather than dragging from corner to corner—essential for precise positioning.

3. In the Ellipse options dialog, set both the Width and Height to 2 in and click OK. This ensures a perfect circle rather than an oval.

4. With the Selection tool , select the circle you just created, then Shift–click on the dark green rectangle behind it. Both objects should now be selected.

5. Navigate to Object > Compound Path > Make to reveal the hidden image beneath. Notice how the compound path creates a transparent "window" through the door, essentially subtracting the circle from the rectangle. This is the fundamental principle behind all compound path operations.

Creating a Second Compound Path

Let's reinforce this technique by creating another window with slightly different dimensions. Varying the sizes creates visual interest and demonstrates the flexibility of the compound path workflow.

1. Select the Ellipse tool once again.

2. Option–click (Mac) or ALT–click (Windows) in the center of Door 2's dark panel. Remember to click once cleanly rather than clicking and dragging.

3. In the Ellipse options, set the Width and Height to 1.75 in, then click OK. This slightly smaller circle creates variety in your composition.

4. Select the new circle and Shift–click the rectangle beneath it, then execute Object > Compound Path > Make. You should now see two doors with perfectly cut circular windows.

Editing Compound Paths

One of the most powerful aspects of compound paths is their non-destructive nature. Unlike raster-based cutouts that permanently alter your artwork, compound paths remain fully editable. This flexibility is crucial for client work where revisions are inevitable, and it's a key advantage that keeps vector workflows efficient in professional environments.

1. Using the Ellipse tool , Option–click (Mac) or ALT–click (Windows) in the center of the dark panel on Door 3.

2. Set the Width and Height to 1.5 in and click OK to create the smallest window of the three.

3. Select both the circle and rectangle for Door 3, then apply Object > Compound Path > Make.

4. The window might not be showing the most interesting part of the underlying image. To fix this, first deselect everything by clicking on empty artboard space, then use the Group Selection tool to target just the circular path within the compound path. You may need to click directly on the circle's edge to select it properly.

5. With the circle selected, switch to the Selection tool to reveal the bounding box handles.

6. Position your cursor over a corner handle, then Shift–click and drag to resize proportionally as shown below. The Shift key constrains the proportions, preventing your perfect circle from becoming distorted into an oval.

   

7. After resizing, switch back to the Group Selection tool to reposition the circle and reveal more compelling portions of the elephant image beneath. This fine-tuning capability demonstrates why compound paths are indispensable for professional design work.

8. Save your file to preserve your progress.