The shape of things
The dynamics behind creating shapes in graphic design software
By Stephen Romaniello
Early graphics software had tools that enabled the user to quickly draw basic shapes such as rectangles, circles, triangles, and polygons. In those days, shapes were drawn with pixels. After a few years, though, vector software emerged that revolutionized the accuracy and editability of shape tools. Adobe Illustrator 1.0 was released in 1987 with a major upgrade (Illustrator 88) in 1988 for Macintosh computers. Illustrator’s competitors in the late 80s included Aldus Freehand, released in 1988, and CorelDRAW for Windows, released in 1989. These products introduced a revolutionary methodology into graphics workflow.
Core dynamics
The early innovation of these software products was their use of PostScript vector graphics. The software’s algorithms are built around vector geometry. Shapes are mathematically defined rather than based on pixel distribution giving them flexibility, precision, and scalability. Shapes are created from paths, anchor points, and curves. They can be scaled infinitely without losing quality and are useful for the creation of logos, print graphics, illustrations, and typography.
Figure 1. Vector software uses Bézier curves, or mathematically defined paths, to create smooth, scalable lines and shapes from a few control points.
Figure 2. Illustrator’s shape tools.
Bézier curves
French engineer, Pierre Bézier, developed the first vector-based software in the 1960s at Renault for automobile body design. It later became the foundational methodology for computer aided design (CAD), typefaces, and illustration. Vector software uses Bézier curves, or mathematically defined paths, to create smooth, scalable lines and shapes from a few control points (Fig. 1). Instead of drawing lines pixel by pixel, anchor points (nodes) are deposited where the curve begins and ends, and direction handles (control points) determine the curve’s direction and shape.
Generating shapes
Several items in the Toolbars of vector software generate paths. In vector software such as Adobe Illustrator or CorelDRAW, the vector tools are similar. They both feature Pen tools for anchor point generation and Path Editing tools for direction handle and segment editing.
They also have individual tools that generate shapes such as rectangles, round-cornered rectangles, polygons, stars, lines with arrowheads or dashed strokes, and ellipses with proportional constraints (Fig. 2). Each of these tools have controls that edit polygons by determining the number of sides, stars by adjusting the number of points and inner radii, lines that can have arrowheads or dashed strokes, ellipses with proportional constraints, and round-cornered rectangles with controls over the corner radii. In short, any standard shape can be generated and modified, and an organic shape can be built with the pen tool and edited with the selection tools.
Figure 3. Menus that offer size, variable width, and style options.
Figure 4. Both the stroke and fill of the shape can be colored with a solid color, gradient, or pattern, and a gradient mesh can be used to model the shape.
Stroke & fill
Specific stroke and fill characteristics can be applied to vector shapes. A width, from .25px to 1000px can be assigned outlining the shape with a uniform line. Menus control stroke size, variable width, and style options (Fig. 3). Both the stroke and fill can be colored with a solid color, gradient, or pattern (Fig. 4).
Outline stroke
Any sized stroke can be easily converted into a shape. Its contours can then be edited by dragging anchor points. To convert a stroke into a shape, choose Object > Path > Outline Stroke. Drag the anchor points to modify the shape. If necessary, add or delete anchor points with the Add/Delete Anchor Point tools found in the Pen tool fly out (Fig. 5).
Figure 5. Choose Object > Path > Outline Stroke and drag the anchor points to modify the shape.
Figure 6. Click Generate, and the AI feature produces three vector art variations of your prompt.
Generative fill
Artificial Intelligence has found its way into vector-based software. In CorelDraw, it’s AI Generate is used to create images from text prompts. In Illustrator there are two commands; Gen Shape Fill and Generate Vectors, both in Object menu. Both display dialog boxes that contain controls to designate styles, effects, color, and tone. Click Generate, and the AI feature produces three vector-art variations of your prompt (Fig. 6). Repeat the process if you want to see more examples. In Illustrator, the AI feature uses Adobe’s vast database called Adobe Firefly. Recent Corel tools may include or connect to generative systems that work similarly to Adobe Firefly. The vector art that is generated in both programs is fully editable using the software’s vector tools.
Pathfinder
Adobe Illustrator’s Pathfinder panel (Fig. 7) is a shape-building and vector-editing powerhouse that modifies shapes automatically. CorelDRAW has a similar feature called the Shaping Docker found under Object > Shaping. These features work on selected overlapping objects, using Boolean operations that save time by automatically transforming them.
The Shape Mode (top row) creates or preserves compound shapes featuring the following commands:
- Unite merges selected shapes into one larger shape.
- Minus Front subtracts the top object from the object behind it.
- Intersect preserves only the overlapping area.
- Exclude removes overlap and keeps non-overlapping areas.
The Pathfinder Operations (bottom row) are a bit more aggressive in cutting objects into multiple shapes.
- Divide cuts all overlapping shapes into separate pieces.
- Trim removes hidden parts behind front objects.
- Merge like Trim but merges same-colored adjacent shapes.
- Crop uses the top object like a cookie cutter.
- Outline turns filled shapes into edge-only paths.
- Minus Back subtracts back object from front object.
Compound path
In Illustrator, a compound path is a single object made from two or more paths that interact to create a transparent hole. In CorelDRAW, the same effect is achieved by choosing Object > Combine. The idea is relatively simple. Think of it like cutting shapes out of paper. The topmost shape cuts a hole in the bottom shape (Fig. 8). Compound paths create holes like letters like B, O, A, P, Q, R. They make transparent cutouts and combine multiple objects into one editable vector object. Even though they are composed of two or more editable objects, they exist on a single layer as a unique object.
Figure 7. Adobe Illustrator’s Pathfinder panel is a shape-building and vector-editing powerhouse that modifies shapes automatically.
Figure 8. With a compound path, the top-most shape cuts a hole in the bottom shape.
Dynamic Tools
A series of additional tools and commands are useful for modifying or combining shapes. The Shape Builder is pathfinder-like function in tool form. Found in the Toolbar panel, it quickly combines multiple shapes into a single shape taking on the color characteristics of the first shape selected with the tool (Fig. 9).
Another dynamic tool is the Shaper tool. If you draw a very rough outline of a shape with this tool it automatically transforms it to a proper hard-edged shape of comparable size.
Live corners
Both Illustrator and CorelDraw shape tools create live corners. When a shape is drawn, a corner node indicates the control point. Dragging the node inward modifies the roundness of all the corners of the shape (Fig. 10). The exception of course, is the Ellipse tool which has no corners. Its node eliminates the circumference of the ellipse and replaces it with an angle.
Figure 9. The Shape Builder combines multiple shapes into a single shape.
Figure 10. When a shape is drawn, a corner node indicates the control point. Dragging the node inward modifies the roundness of all the corners of the shape.
Live corners
Both Illustrator and CorelDraw shape tools create live corners. When a shape is drawn, a corner node indicates the control point. Dragging the node inward modifies the roundness of all the corners of the shape (Fig. 10). The exception of course, is the Ellipse tool which has no corners. Its node eliminates the circumference of the ellipse and replaces it with an angle.
Width tools
Shapes can be radically modified using a series of tools that produce dramatic results. In Illustrator, they are found in the Width tool flyout. In CorelDRAW, though less precise, similar effects are achieved with brushes. The flyout consists of Width, Warp, Twirl, Pucker, Bloat, Scallop, Crystalize, and Wrinkle. The characteristics of each tool are controlled within a dialog box that is displayed by clicking on the tool’s icon. Figure 11 shows the effect of each tool on an ellipse. Applying these tools sometimes creates excessive anchor points. These points complicate the shape. It’s sometimes advisable to simplify the shape. From the Object menu choose Path > Simplify to eliminate superfluous anchor points.
Figure 11. The Width, Warp, Twirl, Pucker, Bloat, Scallop, Crystalize, and Wrinkle tool characteristics are controlled within a dialog box that is displayed by clicking on the tool’s icon.
Figure 12. Photoshop offers a menu of predefined shapes that can be generated at any size or proportion.
Figure 13. A complex vector image is essentially composed of stacks of hundreds of layered shapes.
Raster software
Just as Illustrator and CorelDraw handle pixel-based art, raster programs such as Adobe Photoshop and Corel PaintshopPro have built in vector tools that differ slightly from their vector-based counterparts. The main difference is that when a shape is generated, a “shape” layer is created with a vector mask that defines the shape. Like vector software, the shapes are edited with the Path Selection or Direct Selection tools. Shapes can be created in three modes; as shapes, paths, or pixels. Photoshop offers a large menu of predefined custom shapes that can be generated at any size or proportion (Fig. 12) New shapes created with the vector tools can be added to the menu.
Stacks
Creating shapes with precision is fundamental to illustration. A complex vector image like the one in Figure 13 is a stack of hundreds of layered shapes combined to produce a cohesive picture. Each shape is manually drawn with the vector tools, assigned properties like strokes and fills, and placed where it belongs. It is essential to understand the tools and commands of creating and manipulating shapes, their potential, and where they are and how they function. This knowledge will increase your enjoyment and efficiency and enhance your creativity in the image making process.
Stephen Romaniello is an artist and educator who has seen the evolution of digital graphics since the beginning of the digital revolution in the 1980s. He is CEO of GlobalEye Systems, a graphics software and creative imaging consultancy, and founder of Gorilla Geeks, a creative consulting firm.
