How to Use Sketch Relations in SolidWorks: Simple Guide

In SolidWorks, use sketch relations to define how sketch entities like lines and points relate to each other, such as making them parallel or equal length. You add relations by selecting sketch entities and choosing the desired relation from the PropertyManager or context menu to control geometry behavior automatically.

Syntax

Sketch relations in SolidWorks are applied by selecting one or more sketch entities and then choosing a relation type. Common relations include Horizontal, Vertical, Coincident, Equal, and Parallel.

Each relation defines a geometric or positional rule between entities:

• Horizontal: Makes a line or points align horizontally.
• Vertical: Aligns entities vertically.
• Coincident: Forces points or endpoints to share the same location.
• Equal: Makes lengths or radii equal.
• Parallel: Makes lines parallel.

You apply relations through the PropertyManager after selecting entities or by right-clicking and choosing from the Relations menu.

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Select one or more sketch entities -> Right-click -> Add Relations -> Choose relation type (e.g., Horizontal, Vertical, Coincident, Equal, Parallel)

Example

This example shows how to make two lines equal in length and parallel using sketch relations.

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1. Draw two separate lines in a sketch.
2. Select both lines by clicking them while holding Ctrl.
3. In the PropertyManager, click <strong>Add Relation</strong>.
4. Choose <code>Equal</code> to make their lengths the same.
5. With both lines still selected, add another relation and choose <code>Parallel</code>.
6. The lines will now stay equal in length and parallel when moved or edited.

Output

Two lines remain equal in length and parallel regardless of how you move or resize them in the sketch.

Common Pitfalls

Common mistakes when using sketch relations include:

• Applying conflicting relations that cause errors, like making a line both horizontal and vertical.
• Over-constraining the sketch by adding too many relations, which prevents editing.
• Not selecting the correct entities before adding a relation, leading to no effect.
• Ignoring the Fully Defined status, which helps ensure the sketch is properly constrained.

Always check the sketch status bar to avoid over or under-constraining.

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Wrong way:
Select one line -> Add Horizontal relation
Select same line -> Add Vertical relation

Right way:
Choose either Horizontal or Vertical based on design intent, not both.

Quick Reference

Relation Type	Description	Use Case
Horizontal	Aligns entities horizontally	Make a line flat or points level
Vertical	Aligns entities vertically	Make a line straight up/down
Coincident	Forces points to share location	Attach endpoints or points together
Equal	Makes lengths or radii equal	Keep circles or lines same size
Parallel	Makes lines parallel	Keep lines running in same direction
Perpendicular	Makes lines at 90 degrees	Create right angles
Tangent	Makes curve tangent to line or arc	Smooth transitions between curves and lines

Key Takeaways

Use sketch relations to control how sketch parts behave and relate to each other.

Select the correct entities before adding relations to avoid errors.

Avoid conflicting or too many relations to prevent over-constraining.

Common relations include Horizontal, Vertical, Coincident, Equal, and Parallel.

Check the sketch status bar to ensure your sketch is fully defined.