8.2 Rectangular & Polar Arrays

Copying the same object dozens of times by hand — a row of parking-lot stripes, a ring of bolt holes — is exactly the kind of repetitive work AutoCAD's array tools were built to eliminate. The ARRAY command family produces multiple evenly spaced copies of selected objects in a single operation, and the ACU AutoCAD exam focuses on its two most common patterns: rectangular grids and polar (circular) distributions.

ARRAY, ARRAYRECT, and ARRAYPOLAR

Typing ARRAY opens a Type prompt offering Rectangular, Polar, or Path array (Path arrays follow a curve or line and fall outside this exam's scope). Typing ARRAYRECT or ARRAYPOLAR directly skips that Type prompt and jumps straight into the corresponding array type, which is the faster route when you already know which pattern you need.

Rectangular Arrays: Rows, Columns, and Levels

An ARRAYRECT arrangement is defined by three counts and their associated spacing:

After selecting objects, the contextual Array Creation ribbon (or the equivalent command-line options: Associative, Base point, COunt, Spacing, COLumns, Rows, Levels, eXit) lets you set the column count and column spacing, the row count and row spacing, and optionally a level count and level spacing. Spacing can be entered either as the distance between adjacent copies or as the total distance the entire array should span, and AutoCAD calculates the other value automatically once you've fixed one of them. A negative spacing value flips the array's direction — for example, a negative row spacing builds the array downward instead of upward from the base selection.

Polar Arrays: Center Point, Item Count, and Fill Angle

An ARRAYPOLAR arrangement starts with a center point (the point every copy is distributed around), and is otherwise defined by two related values: the number of items and the fill angle — the total angular sweep across which those items are distributed, measured in degrees. The default fill angle is 360°, producing a complete ring of evenly spaced copies, but a smaller fill angle produces a partial arc of copies instead, such as a fan of 5 items spread across only 90°.

When a full 360° fill angle is used, the angular spacing between adjacent items equals the fill angle divided by the item count. Eight bolt holes distributed around a full circle, for instance, land 360÷8 = 45° apart. If the fill angle is instead reduced to 90° while keeping 8 items, an option to specify the angle between items directly (rather than a total fill angle) becomes the more natural way to define spacing, since AutoCAD also lets you set item count and angle-between-items as the two controlling values instead of item count and total fill angle — either pairing determines the other automatically.

Rotate Items As Copied

A polar array includes a Rotate items as copied setting, on by default. With it on, each copy rotates to maintain the same orientation relative to the center point as the original — a directional arrow copied around a circle keeps pointing outward (or inward) at every position, the way spokes radiate from a wheel's hub. Turning this setting off keeps every copy in the exact same orientation as the original object, without any rotation applied as it's placed around the circle — useful when the copied object (like a text label or a north arrow) needs to stay upright and readable at every position rather than tilting to match its position on the ring.

Associative Arrays and ACU-Level Editing

Both ARRAYRECT and ARRAYPOLAR create an associative array by default: all of the copies behave as a single linked object rather than a set of independent duplicates. Selecting an associative array displays special array grips — distinct from the grips on an ordinary object — that let you adjust the array without reopening the command. Dragging a column-spacing grip changes the spacing for every column in the array simultaneously; dragging a count grip adds or removes columns, rows, or polar items across the whole array at once; dragging the array's base grip repositions the entire pattern as a unit.

The ARRAYEDIT command re-enters an existing associative array to make more structural changes — replacing which objects the array is built from, or editing one specific item within the array independently of the rest (called making that item's properties "unique" while the remaining items stay linked to the array definition).

An associative array can be broken apart with EXPLODE, converting it into a set of ordinary, independent copies. Once exploded, moving, rotating, or otherwise editing one copy no longer has any effect on the others, since the underlying array link has been removed entirely. Alternatively, setting the Associative option to No at creation time skips the linked behavior from the start, producing plain independent copies immediately with no array-level grips or ARRAYEDIT access available afterward.

Worked Examples

Rectangular: A row of parking-space stripe lines needs 6 columns spaced 9 feet apart and 1 row (a single line of stripes, no depth repetition). Selecting the stripe object, running ARRAYRECT, and entering 6 columns with 9-foot spacing (and 1 row) produces 6 evenly spaced copies spanning a total width of 5 × 9 = 45 feet from the first stripe's position to the last.

Polar: A flange plate needs 6 bolt holes evenly spaced around its full circumference. Selecting the hole circle, running ARRAYPOLAR, picking the flange's center point, and entering 6 items across the default 360° fill angle produces holes spaced 360÷6 = 60° apart around the ring.

On the Exam

Expect questions asking you to calculate the angle between polar array items given a fill angle and item count, to identify which of rows/columns/levels corresponds to which axis, and to distinguish an associative array's linked, grip-editable behavior from an exploded array's independent copies. Confusing Rotate items on/off, or assuming a negative spacing value produces an error rather than simply flipping direction, are common wrong-answer traps.