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description: "Illustrator Basics — Illustrator is a vector editor: shapes are stored as mathematical paths (points and curves) rather than a grid of pixels, so they…"---

03 · Illustrator Basics

Illustrator is a vector editor: shapes are stored as mathematical paths (points and curves) rather than a grid of pixels, so they scale to any size — a business card and a billboard — with no loss of sharpness. This module covers the workspace, artboards, basic shapes, the Pen tool, and the vector-vs-raster distinction that decides when you reach for Illustrator instead of Photoshop.

1. Workspace tour

1. Open Illustrator and create a new document: File > New (⌘/Ctrl+N). Pick any preset (e.g. Web at 1000×1000 px) and click Create.
2. The layout mirrors Photoshop's: Toolbar (left), Options/Control bar (top), Artboard/canvas (center), Panels (right — Layers, Properties, Swatches, Stroke).
3. Every panel is reachable via the Window menu if it's not docked — Window > Layers, Window > Stroke, etc.
4. Zoom with ⌘/Ctrl + / ⌘/Ctrl -; ⌘/Ctrl+0 fits the active artboard in the window. Hold Space and drag to pan.

2. Artboards

An artboard is Illustrator's equivalent of a page or canvas boundary — and unlike Photoshop, a single Illustrator document can hold many artboards, useful for a set of related assets (e.g. a logo at three sizes, or three social-media post variants) in one file.

1. Press Shift+O to select the Artboard tool. Drag on an empty part of the canvas to create a new artboard; drag an existing artboard's edge handles to resize it.
2. Window > Artboards lists every artboard in the document and lets you rename, reorder, or duplicate them.
3. To duplicate an existing artboard along with everything on it, select it with the Artboard tool and Option/Alt-drag it to a new position.
4. Each artboard exports as its own file when you use File > Export > Export As with Use Artboards checked — handy for producing several sized logo variants from one source file (used in Module 7 and the Module 10 capstone).

3. Basic shapes

1. Press M for the Rectangle tool (cycle Shift+M for Rounded Rectangle), L for the Ellipse tool. Drag on the canvas to draw; hold Shift while dragging to constrain to a perfect square/circle.
2. Every shape has both a Fill (interior color) and a Stroke (outline) — set both from the color swatches at the bottom of the Toolbar, or the Window > Color panel for precise values.
3. The Selection tool (V) moves and resizes whole shapes; the Direct Selection tool (A) selects and drags individual anchor points or path segments within a shape — you'll need Direct Selection constantly once you start editing paths in Module 7.
4. Shapes support live corner-radius handles: with the Selection tool active, click a rectangle to reveal small circular handles at its corners — drag one to round all four corners live, non-destructively.

4. The Pen tool — fundamentals

The Pen tool (P) draws arbitrary paths point-by-point and is the core skill that separates basic Illustrator use from real vector drawing — it's how logos, icons, and custom shapes actually get built.

1. Click once to place a straight-line anchor point; click again elsewhere to draw a straight segment between the two points.
2. Click-and-drag (instead of a plain click) to place an anchor point with curve handles — dragging out further makes the curve on either side of that point more pronounced.
3. Close a path by clicking back on the very first anchor point (a small circle appears next to the pen cursor when you're hovering over it, confirming it will close the path).
4. Press Esc or select a different tool to end an open path without closing it.
5. While actively drawing, hold Option/Alt and click a curve point to convert it to a corner point for the next segment — this is how a single path mixes smooth curves and sharp corners (e.g. a speech-bubble shape).
6. Use the Direct Selection tool (A) afterward to click and drag individual anchor points or their curve handles to refine a path you've already drawn.

The Pen tool has a learning curve — that's normal

Getting smooth, evenly-spaced curves with the Pen tool takes practice. A reliable way to build intuition: trace the outline of a simple round logo or icon placed on a locked layer beneath your drawing layer, using as few anchor points as possible — fewer, well-placed points make smoother curves than many closely-spaced ones.

5. Vector vs. raster

This is the single most important concept to internalize before moving between Illustrator and Photoshop:

	Vector (Illustrator)	Raster (Photoshop)
Stored as	Math (points, curves, fills)	A grid of colored pixels
Scaling	Infinite, no quality loss	Loses sharpness past original resolution
Best for	Logos, icons, type, illustrations	Photos, painted/composited images
File formats	.ai, .svg, .eps	.psd, .jpg, .png (as a raster)

You can bring a raster image into Illustrator (File > Place) to trace or use as reference, and you can bring vector art into Photoshop, where it becomes a Smart Object that stays somewhat scalable within Photoshop but ultimately renders to pixels once flattened. But a vector path itself — the anchor points and curves — cannot be "converted back" from a rasterized image; once flattened to pixels, the underlying path math is gone. This is why logos should always be designed and archived in Illustrator, even if a raster export is what actually ships.

Cheat sheet

Tool/Action	Shortcut
New document	⌘/Ctrl+N
Artboard tool	Shift+O
Rectangle tool	M
Ellipse tool	L
Selection tool (move/resize whole shapes)	V
Direct Selection tool (edit anchor points)	A
Pen tool	P
Constrain shape to square/circle while dragging	Shift
Place a raster image	File > Place
Export artboards (with sizes/formats)	File > Export > Export As
Fit artboard to window	⌘/Ctrl+0

How It Actually Works

Understanding what a path is under the hood explains why vector editing behaves so differently from raster editing.

• A path is a sequence of Bézier segments, defined by four numbers per segment. Each anchor point stores an x/y position plus two optional control-handle offsets (in/out). The curve between two anchors is a cubic Bézier: the renderer walks a parametric variable t from 0 to 1 and evaluates a weighted blend of the two anchor positions and their two handles at each step. This is why dragging a handle further out makes a curve "more pronounced" — you're increasing the weight that control point contributes to the blend, not manually reshaping pixels.
• Scaling is re-evaluating the same math at new coordinates, not resampling an image. When you scale a vector shape up, Illustrator just multiplies every anchor and handle coordinate by the scale factor and re-renders the Bézier curves at the new size — there's no original data to "run out of," which is the literal reason a vector logo scales to a billboard with identical sharpness. A raster image, by contrast, has to interpolate brand-new pixel values between the ones it actually has, which is inherently a guess.
• Fill and Stroke are rendered as two separate operations on the same path geometry. The Fill rasterizes everything enclosed by the path's boundary (using its winding rule to decide "inside" for self-intersecting or compound paths); the Stroke is a second pass that traces a ribbon of a given width, centered on (or offset from) the same path outline. This is why a corner-radius or Pen-tool edit updates both instantly and identically — they read from one shared path, not two independently drawn outlines.
• Placing a raster image doesn't convert it — it embeds or links a bitmap object alongside your vector art. Illustrator's canvas is a mixed-model document: some objects are vector paths, others (placed images) are references to pixel data with their own transform matrix. The Pen tool and path math never touch that pixel data; that's exactly why "tracing" a placed photo with the Pen tool is a fully manual, human judgment call — Illustrator has no automatic bridge from pixel edges back to anchor points (Image Trace, covered later, approximates this algorithmically but produces its own new path data, not a recovery of an "original" vector).
• A closed path is stored as a loop with an explicit closing flag, not just anchors that happen to line up — which is why clicking back on the first anchor snaps and locks the path shut (enabling fill) rather than merely placing a coincident final point; an open path with visually touching endpoints still renders with no fill and behaves differently under operations like Offset Path or the Pathfinder tools you'll use in Module 7.

Exercise

Create a new document with three artboards side by side (use Window > Artboards to confirm you have exactly three). On the first, draw a rounded rectangle and a circle with a Fill and Stroke of your choosing. On the second, draw a simple closed shape using only the Pen tool that mixes at least one straight segment and one curved segment (e.g. a speech bubble or a rounded arrow). Leave the third blank for now — you'll use it in Module 7. Export all three artboards as separate PNGs using **Export As

Use Artboards**.