Geometric relations (horizontal, vertical, coincident, tangent) in Solidworks - Step-by-Step Guide

Introduction

Geometric relations help you control how sketch elements align and connect. They make sure lines and points behave as you want, like staying horizontal or touching each other exactly.

When you want a line to stay perfectly horizontal in your sketch.

When you need two points to always be at the same spot.

When you want a line to be vertical to keep your design straight.

When you want a curve to just touch a line without crossing it.

When you want to lock the position of sketch elements relative to each other.

Steps

Step 1: Select the first sketch entity (line or point)

- Graphics area in the Sketch tab

The entity highlights showing it is selected

Step 2: Hold Ctrl and select the second sketch entity

- Graphics area in the Sketch tab

Both entities highlight indicating multiple selection

Step 3: Click the 'Add Relations' button

- PropertyManager panel on the left

Available geometric relations appear for selection

Step 4: Choose the desired relation: Horizontal, Vertical, Coincident, or Tangent

- PropertyManager panel under 'Add Relations'

The selected relation applies and entities adjust accordingly

Step 5: Click the green checkmark to confirm

- PropertyManager panel

Relation is saved and sketch updates visually

Before vs After

Before

Two lines are free and can be placed anywhere without alignment

After

One line is locked horizontal and the other is tangent to a curve, adjusting automatically when moved

Settings Reference

Add Relations

📍 PropertyManager panel during sketch editing

Defines how sketch entities relate and behave to each other

Default: No relation applied

Display/Delete Relations

📍 Sketch tab > Display/Delete Relations button

Manage existing geometric relations in the sketch

Default: Show all relations

Common Mistakes

Trying to apply a horizontal relation between two points instead of lines

Horizontal relation only applies to lines or linear entities, not points

Select lines to apply horizontal or vertical relations; use coincident for points

Applying conflicting relations causing sketch errors

Conflicting relations make the sketch over-defined and unstable

Check existing relations before adding new ones to avoid conflicts

Summary

Geometric relations control how sketch elements align and connect.

Use horizontal and vertical to keep lines straight, coincident to join points, and tangent to touch curves.

Avoid conflicting relations to keep sketches stable and easy to edit.