8.1 Linear Pattern

8.1 Linear Pattern

Quick Answer: Insert → Pattern/Mirror → Linear Pattern copies a seed feature (or body) along Direction 1 and optionally Direction 2. Set spacing and number of instances (count includes the seed). Match the drawing’s hole/boss grid, skip missing instances when required, then re-check Mass Properties after any spacing or count change.

On CSWA part questions—especially basic and intermediate modification items—drawings almost always include repeated geometry: bolt-hole patterns on a flange, rib bosses on a plate, cut slots in a row, or dual-direction hole grids. Modeling each hole as a separate Extruded Cut wastes time and breaks design intent when the exam says “change hole spacing from 25 mm to 30 mm.” Linear Pattern is the associative tool that answers those edits in one PropertyManager change.

Where Linear Pattern sits on the CSWA skill map

Patterns appear across prep paths (MySolidWorks CSWA Exam Prep and academic topic lists) alongside sketches, extrudes, and mass properties. You will use Linear Pattern when the sheet shows:

• A row of identical features along a straight edge or centerline
• A grid (Direction 1 × Direction 2) of holes or bosses
• Equal spacing callouts such as 4× Ø8 on a pitch of 40 mm
• Modification language that changes count or pitch without redrawing every feature

Circular arrays belong to Circular Pattern (section 8.2). Reflection across a plane is Mirror (section 8.3). Do not force a circular bolt circle into a linear pattern with awkward angles.

PropertyManager building blocks

Direction 1 and Direction 2

Direction 1 is mandatory. Select a straight model edge, a sketch line, a temporary axis, or another linear reference that defines the array travel. The preview arrows show positive sense; use Reverse Direction if copies stack the wrong way relative to the seed.

Direction 2 is optional. Enable it when the drawing shows a 2D grid (for example, 3 holes along X and 2 along Y). Each direction has its own spacing and instance count. Total theoretical instances for a full rectangular pattern are roughly (N1) × (N2) with the seed shared—SOLIDWORKS builds the rectangular array from the seed; verify the preview against the drawing rather than hand-multiplying blindly if options like “pattern seed only” or skipped instances are active.

Exam habit: Align Direction 1 with the primary pitch dimension shown on the view (often the longer row). Align Direction 2 with the secondary pitch. If the seed is not at a corner of the grid, either relocate the seed feature to a corner/end position the drawing treats as the origin of the array, or plan skips—corner seeds are usually cleaner for timed exams.

Spacing modes: fixed spacing vs up to reference

SOLIDWORKS Linear Pattern supports more than one way to drive pitch:

Fixed spacing (most common on CSWA)

You type a spacing value equal to the center-to-center distance between consecutive instances. Example: three holes, 30 mm apart → Spacing = 30 mm, Instances = 3. The last instance sits at (N − 1) × spacing from the seed along that direction.

Up to reference / distance-driven layouts

Some workflows define the array so instances fill a distance up to a selected reference (face, plane, or edge) rather than only a raw pitch box. When the drawing gives an overall length from first to last hole plus a count, you may either:

1. Compute spacing = overall / (N − 1) and enter fixed spacing, or
2. Use reference-driven options when the UI exposes “up to reference” style controls for the direction

Exam trap: Using overall length as if it were spacing. If first-to-last is 80 mm for 5 holes, spacing is 80 / 4 = 20 mm, not 80 mm. Wrong spacing explodes or collapses the pattern and mass fails immediately.

Instance count includes the seed

This single rule causes more wrong answers than almost any other pattern detail:

• Number of Instances = total positions in that direction, including the original seed feature.
• To add three copies beyond the seed, set instances to 4, not 3.

Worked example: Seed hole at left. Drawing shows four identical holes in a horizontal row. Set Instances = 4, Spacing = pitch. Result: seed + three patterned holes = four total.

If mass is roughly 25% light or heavy versus expectation after a hole pattern, recount instances before rebuilding the whole part.

Features vs bodies (and multi-feature seeds)

Features to Pattern

Typical CSWA choice: select the Extruded Cut (or Hole Wizard feature, boss, etc.) that creates one instance. Child features can be included when the seed is a stack (for example, a boss plus a fillet on that boss)—select every feature that must travel with each copy.

Incomplete seed selection trap: You pattern only the cut but leave a related chamfer or cosmetic thread only on the seed. Mass may still be close, but geometry and later mates will not match. Select all features that define one “unit” on the drawing.

Bodies to Pattern

When working multi-body (less common on pure associate part items but appears in some advanced builds), Bodies to Pattern duplicates entire solid bodies. Do not confuse this with patterning a feature that removes material from a single body—wrong scope creates extra bodies or fails boolean expectations.

Geometry Pattern option

Geometry Pattern (checkbox in the PropertyManager) copies the resulting geometry of the seed without fully re-solving each instance as an independent feature regenerate in the same way as a standard pattern. Benefits and costs:

CSWA guidance: Leave Geometry Pattern off unless you know you need it for performance or a known case. If a patterned cut should always go Through All relative to the local body state, standard feature patterning is safer. If mass is wrong after enabling Geometry Pattern, turn it off and rebuild.

Skip instances

Drawings sometimes show a full grid with one hole missing (clearance for a boss, cable path, or casting core). Workflow:

1. Build the full logical pattern (correct N and spacing).
2. Expand Instances to Skip (or click pink markers in the graphics area, depending on version UI).
3. Skip the instance(s) that the drawing leaves empty.
4. Confirm preview: no solid cut/boss where the sheet is blank.

Skipping after the fact is better than building irregular patterns with mixed manual features—modification steps that change pitch still update remaining holes together.

Seed feature quality (design intent before pattern)

Pattern only amplifies the seed. A bad seed makes N bad copies.

1. Fully define the seed sketch; correct diameter and position relative to datums.
2. Use end conditions that remain valid when copied (Through All, Up to Next, blind depth as drawing requires).
3. Prefer patterning Hole Wizard or a single cut feature rather than a fragile stack of unrelated sketches.
4. Place the seed where the drawing’s first instance sits so directions and counts read naturally.

Blind vs Through All: If each patterned hole must break through a stepped thickness, Through All (or appropriate end condition) on the seed usually patterns more reliably than a blind depth sized only for the seed location.

Modification questions: spacing, count, and mass

CSWA numeric items often use a two-step pattern:

1. Build the part with initial pitch/count; optionally record mass.
2. “Change linear spacing from 20 mm to 25 mm” or “change from 4 holes to 6 holes,” then report new mass or CoM.

Under the clock:

1. Find LPattern (or named pattern) in the FeatureManager—do not delete and recreate.
2. Edit Feature → change Spacing and/or Number of Instances.
3. Update Instances to Skip if the new count changes which slots are empty (re-read the modified drawing).
4. Rebuild; fix any failures (pattern extending off the body, zero-thickness faces).
5. Confirm material still applied.
6. Mass Properties → enter the value with required decimals (often two places, MMGS).

Mass intuition (verify, do not guess): More hole instances generally decrease mass; larger spacing does not remove material by itself if count and hole size stay equal—but CoM can shift as holes move. Changing boss patterns can increase mass with more instances. Always re-measure.

Linear vs Circular vs Mirror (chooser)

A 2-instance linear pattern can fake a “pair” of holes, but if the rest of the part is symmetric about a plane, Mirror may better match design intent for later symmetric edits (see 8.3).

Practical CSWA checklist for Linear Pattern

1. Create one correct seed feature; fully define it.
2. Start Linear Pattern; select all seed features that belong to one unit.
3. Set Direction 1 (and 2 if grid); reverse if needed.
4. Enter spacing = pitch, not overall length unless you converted correctly.
5. Set instances = total including seed.
6. Skip instances that the drawing omits.
7. Leave Geometry Pattern off unless you have a reason.
8. Rebuild; visual check against every hole/boss on the sheet.
9. On modification, edit pattern parameters in place → Mass Properties.

Linear Pattern is high leverage: one seed plus correct N and pitch can replace a dozen manual features and still absorb the spacing/count edits that CSWA uses to re-score mass. Treat instance count and pitch arithmetic with the same care as extrude depths.