Component Patterns and Mirroring in Assemblies

Overview

Component patterns enable efficient replication of parts or sub-assemblies within a larger design environment. Rather than placing and mating each component individually, patterns use existing layouts or user-defined repeating rules to automate placement — saving time, ensuring consistency, and capturing design intent.

Key Concepts

• Mirroring – Creating symmetric copies of components across a reference plane
• Linear Pattern – Replicating components along one or two straight directions
• Circular Pattern – Replicating components radially around a central axis
• Feature Driven Pattern – Replicating components based on an existing pattern feature within the assembly

Mirroring Components

• Purpose: Best suited for symmetric assemblies where one half mirrors the other
• Defining the Mirror:
  • Requires a mirror plane — a standard reference plane, user-created plane, or any flat face within the assembly
  • Requires selecting the components to mirror — single parts or sub-assemblies
• Orientation and Alignment:
  • A preview of the mirrored components is generated before confirmation
  • Simply mirroring geometry may produce incorrect alignment depending on the component's original symmetry
  • Users can cycle through different orientation options to find the correct alignment
• Opposite Hand Versions:
  • Required when no standard orientation aligns correctly (common with non-symmetric parts)
  • Generates a completely new, mathematically mirrored version of the original part
  • Can be saved as:
    • A derived configuration within the existing part file
    • An entirely new file (with options for prefixes, suffixes, or custom names)
  • A link to the original file can be maintained so changes propagate automatically
• Managing Mirrored Components:
  • Creates a dedicated MirrorComponent feature in the design tree
  • Moving the original component causes mirrored components to reposition symmetrically
  • Mates from the original are not explicitly copied — the geometric relationship is maintained by the mirror feature itself

Linear Patterns

• Purpose: Replicating a component or sub-assembly multiple times along one or two linear directions
• Defining the Pattern:
  • Direction 1 — defined using a linear vector reference (straight edge, plane normal, or axis); direction can be reversed
  • Spacing — distance between each instance
  • Number of Instances — total count including the original (seed) component
  • Components to Pattern — selection of parts or sub-assemblies to replicate
• Adding a Second Direction (Optional):
  • Creates a grid-like array by defining a second linear vector, spacing, and instance count
  • Pattern Seed Only option — instances in Direction 2 are created only from the original seed, not from all Direction 1 instances
• Skipping Instances:
  • Individual instances can be removed by selecting markers in the graphical preview
  • Skipped instances can be restored later by editing the pattern feature
• Managing Linear Patterns:
  • Creates a single feature in the design tree containing all patterned instances
  • Position is controlled entirely by pattern parameters (spacing, direction) relative to the seed
  • No new mates are created for patterned instances

Circular Patterns

• Purpose: Replicating a component or sub-assembly multiple times radially around a central axis
• Defining the Pattern:
  • Pattern Axis — defines the center of rotation; valid selections include cylindrical faces, circular edges, or explicit axes (including temporary axes)
  • Components to Pattern — selection of parts or sub-assemblies to replicate
• Spacing Options:
  • Equal Spacing — instances distributed evenly over a specified total angle (e.g., 360° for a full circle)
  • Specific Angle — user defines the exact angle between each instance
• Management:
  • Instances can be skipped, same as linear patterns
  • Controlled by a single feature in the design tree
  • Common use case: distributing fasteners (screws, bolts) around a circular layout

Feature Driven Patterns

• Purpose: Replicating a component based on an existing pattern feature (linear, circular, or hole wizard) already present on a part within the assembly
• Why Use It: The most robust method when components must align precisely with patterned features on another part
• Defining the Pattern:
  • Components to Pattern — the seed component
  • Driving Feature — the existing pattern (e.g., a hole pattern on a base plate) selected from the design tree
• Workflow Example (Fasteners):
  1. A plate contains a circular pattern of holes
  2. A single fastener is manually mated into the first hole (seed position)
  3. A Feature Driven Pattern is applied — the fastener is the component; the hole pattern is the driving feature
  4. The pattern automatically populates all remaining holes with fasteners
• Advantages:
  • Highly efficient — automatically follows existing design geometry
  • Eliminates manual placement of repeated components
• Time Dependency Rule:
  • The driving feature must exist in the design history before the pattern that relies on it
  • If the base pattern is created after the components intended to be patterned, those components cannot reference it until the design history is reordered

Dissolving Patterns

• Dissolving breaks a pattern feature, converting patterned instances into independent, individual components
• Once dissolved:
  • Components lose their patterned relationship
  • Positions become undefined (no mates)
  • Each component must be mated manually if positional control is needed
• Use dissolution when individual control over a specific patterned instance is required

Comparison of Pattern Types

Pattern Management Comparison

Diagrams

Pattern Type Selection Workflow

flowchart TD
    A[Need to Replicate Components] --> B{Is the assembly symmetric?}
    B -- Yes --> C[Use Mirror]
    B -- No --> D{Do patterned features already exist on another part?}
    D -- Yes --> E[Use Feature Driven Pattern]
    D -- No --> F{What layout is needed?}
    F -- Straight rows or grid --> G[Use Linear Pattern]
    F -- Radial / around an axis --> H[Use Circular Pattern]

Mirroring Process

flowchart TD
    A[Select Mirror Plane] --> B[Select Components to Mirror]
    B --> C[Preview Orientation]
    C --> D{Correct Alignment?}
    D -- Yes --> E[Confirm Mirror]
    D -- No --> F{Can cycling orientations fix it?}
    F -- Yes --> G[Cycle Orientation Options] --> D
    F -- No --> H[Create Opposite Hand Version]
    H --> I[Save as Configuration or New File]
    I --> E

Feature Driven Pattern Workflow

flowchart TD
    A[Existing Part Has Patterned Features] --> B[Manually Mate Seed Component into First Position]
    B --> C[Select Feature Driven Pattern]
    C --> D[Select Seed Component]
    D --> E[Select Driving Feature from Design Tree]
    E --> F{Driving Feature Created Before Pattern?}
    F -- Yes --> G[Pattern Auto-Populates All Positions]
    F -- No --> H[Reorder Design History First]
    H --> G

Dissolving a Pattern

flowchart TD
    A[Pattern Feature in Design Tree] --> B[Dissolve Pattern]
    B --> C[Instances Become Independent Components]
    C --> D[Positions Undefined — No Mates]
    D --> E[Manually Mate Each Component as Needed]

Key Terms

• Mirror Plane – The geometric reference (standard plane, custom plane, or flat face) used to establish symmetry for mirroring
• Opposite Hand Version – A mathematically mirrored, distinct new part file or configuration created when standard orientation cycling cannot achieve proper alignment
• Direction Vector – A linear reference (edge, axis, or plane normal) defining the path for a linear pattern
• Pattern Axis – The central line around which a circular pattern revolves
• Seed Component – The original part or sub-assembly being replicated in any pattern type
• Driving Feature – An existing geometric pattern (e.g., patterned holes) used to determine component placement in a feature driven pattern
• Dissolve Pattern – The action of breaking a pattern feature, converting its instances into independent, un-mated components
• Pattern Seed Only – A linear pattern option where Direction 2 instances replicate only from the original seed, not from all Direction 1 instances
• Time Dependency – The requirement that a driving feature must precede its dependent pattern in the design history

Quick Revision

• Mirroring is best for symmetric designs; uses a plane; may require creating an opposite hand version for non-symmetric parts
• Linear Patterns replicate components along one or two straight vectors with defined spacing and count
• Circular Patterns replicate components radially around a central axis using equal spacing or a specific angle
• Feature Driven Patterns replicate components to match an already existing pattern on another part (e.g., placing fasteners in patterned holes)
• No new mates are created by any pattern type — position is controlled by the pattern feature itself
• Skipping instances is available in linear and circular patterns to remove specific copies
• Dissolving a pattern breaks it into independent, un-mated components for individual control
• Time Dependency applies to feature driven patterns — the driving feature must exist earlier in the design history
• Opposite Hand Versions can be saved as a derived configuration or as a new linked file
• Pattern Seed Only controls whether a second direction in a linear pattern replicates from all Direction 1 instances or only the original seed