11.1 Hatches & Fill Patterns

HATCH is the command that fills an enclosed area with a repeating pattern, a solid color, or a smooth gradient, and it is the tool AutoCAD drafters reach for constantly to represent materials in section views, shade a highlighted region, or distinguish one zone of a floor plan from another. The ACU AutoCAD exam tests the two ways of defining a hatch boundary, the properties that control how a pattern looks once it is placed, and the behavior that keeps a hatch attached to (or detached from) the geometry around it.

Starting HATCH and the Two Boundary Methods

Typing HATCH (or H) opens the contextual Hatch Creation ribbon tab and switches the crosshair into boundary-detection mode. From there, two fundamentally different approaches build the boundary that the fill will occupy:

• Pick Points — you click once inside an area that is visually enclosed by existing objects (lines, arcs, polylines, circles, or any combination), and AutoCAD automatically analyzes everything surrounding that point to calculate a closed boundary on the fly. This is the default and by far the most common method, because it requires no advance selection — you simply click inside the space you want filled, and even complex, irregular regions built from multiple separate objects resolve correctly as long as there is no gap in the enclosure.
• Select Objects — instead of clicking inside a space, you directly select the boundary objects themselves (for example, a closed polyline, or a set of individual lines and arcs that form a loop). AutoCAD treats whatever you select as the boundary and fills accordingly, without performing the same enclosed-area analysis Pick Points relies on.

The practical difference shows up when boundaries are imperfect or nested. Pick Points can fail or hatch the wrong region if there is a gap in the surrounding geometry (though a Gap Tolerance setting allows small gaps to be bridged), and it automatically detects islands — closed shapes fully inside the outer boundary — and, depending on the island detection style chosen, either excludes them from the fill (Normal or Outer style) or fills straight through them (Ignore style). Select Objects instead fills exactly what you selected, which is useful when you already have a single closed polyline representing the exact area and want to skip the automatic detection step entirely.

Core Hatch Options: Pattern, Scale, and Angle

Once a boundary is defined, three settings determine the fill's visual character:

• Pattern — chosen from the Hatch Creation ribbon's pattern gallery or the Properties palette, this selects the predefined design (ANSI31 diagonal lines for general-purpose section hatching, AR-CONC for concrete aggregate, steel cross-hatch patterns, and dozens of others) or a Solid fill, or a Gradient fill blending two colors or one color to a tint
• Scale — multiplies the size of the pattern's repeating unit. A pattern designed for architectural drawings at a small scale will look drastically different plotted into a mechanical part drawn at a much larger real-world size, so scale must be adjusted to the drawing's units and eventual plot scale
• Angle — rotates the pattern's lines from their default orientation, commonly used to distinguish adjacent materials in a section view by hatching one region at 45 degrees and an adjacent region at 135 degrees

A hatch pattern that looks like it filled the area with a solid black mass, rather than showing distinct visible lines, is almost always a scale set far too small for the drawing — the repeating lines are packed so closely together that they visually merge. The fix is to increase the hatch scale until individual pattern lines become distinguishable again; decreasing scale would make the problem worse, not better.

Matching an Existing Hatch's Settings

Rather than manually re-entering pattern, scale, angle, and color for every hatched region in a drawing, the Match Properties button on the Hatch Creation ribbon (also called Inherit Properties in the classic Hatch and Gradient dialog) lets you click an existing hatch object in the drawing and copy its full set of settings onto the new hatch being created. This is the standard way to keep multiple hatched areas — for instance, every concrete element in a set of section views — visually identical without retyping the same scale and angle values repeatedly. The general MATCHPROP command can also copy hatch properties onto an existing hatch object after the fact, alongside other shared properties like layer and color.

Hatch Color and Layer

A hatch object carries its own color, independent of the boundary objects around it, set either before creation on the Hatch Creation ribbon's Properties panel or afterward through the Properties palette. Placing hatches on a dedicated hatch layer (rather than mixing them onto the same layer as the boundary geometry) is common drafting practice, since it lets an entire drawing's hatching be frozen, turned off, or globally recolored without touching the underlying model geometry — and it keeps draw order conflicts between hatches and the linework they fill more predictable.

Associative vs. Non-Associative Hatches

By default, a hatch created with HATCH is associative: it remains linked to the boundary geometry that defined it, so if you later stretch, move, or reshape that boundary, the hatch automatically regenerates to fill the new shape. This associativity is what makes HATCH practical in a live design workflow — a section boundary can be adjusted as a design changes, and every hatch inside it updates without manual rework.

A hatch can also be created (or converted) as non-associative, in which case it behaves as an independent object: editing the boundary afterward leaves the hatch exactly as it was originally shaped, now potentially mismatched with the new boundary shape. Associativity can also be broken on an existing hatch through the Set Origin and boundary-editing tools, or simply by deleting the boundary objects the hatch was linked to — once the linked boundary is gone, the hatch keeps its last computed shape but loses the ability to update further.

Editing an Existing Hatch

Double-clicking a hatch object (or selecting it and using HATCHEDIT) reopens the Hatch Editor ribbon contextual tab with every original setting available for change — pattern, scale, angle, associativity, and island detection style can all be revised after the fact. Hatch objects also expose grips: a grip at the origin point (used to control where the pattern starts repeating from), and in many cases a grip that lets you drag to adjust scale interactively. The HATCHTOBACK command sends every hatch in the drawing to the very back of the draw order in one operation, which is a common cleanup step to keep hatch fills from visually covering text, dimensions, or linework that should sit on top of them.

Annotative Hatches

Like text and dimensions, a hatch can be made Annotative, meaning it stores one or more scale representations and automatically displays the correctly sized pattern depending on which annotation scale is active or which viewport it is being viewed through. This avoids creating separate hatch objects at different scales for the same region when a drawing needs to be plotted at more than one scale.

On the Exam

Expect direct questions distinguishing Pick Points from Select Objects (and how each handles gaps or islands), practical troubleshooting questions about a hatch that appears solid black (fix: increase scale), and questions about what Match Properties/Inherit Properties actually copies. Associative behavior — specifically what happens to a hatch when its boundary is edited or deleted — is also a frequently tested scenario.