Construction geometry usage in Solidworks - Step-by-Step Guide

Introduction

Construction geometry helps you create reference shapes that guide your design without affecting the final model. It solves the problem of needing temporary lines or points to build complex parts accurately.

When you need a reference line to align holes or features but don't want it to appear in the final part.

When creating a centerline for symmetrical parts to help with measurements and constraints.

When you want to define angles or distances between features without adding physical edges.

When sketching complex shapes that require helper points or lines to position curves correctly.

When you want to lock geometry in place using references without changing the actual shape.

Steps

Step 1: Open a new or existing sketch

- FeatureManager design tree → Right-click on a face or plane → Select 'Sketch'

The sketch environment opens with drawing tools available

Step 2: Draw a line, point, or other geometry to use as a reference

- Sketch toolbar → Select 'Line' or 'Point' tool

The geometry appears on the sketch but is still normal geometry

Step 3: Select the geometry you want to convert to construction

- Click on the line or point in the sketch

The geometry is highlighted

Step 4: Click the 'For Construction' button

- Sketch toolbar → Click the 'For Construction' icon (a dashed line symbol)

The selected geometry changes to dashed lines indicating construction geometry

💡 You can toggle construction geometry on and off anytime to adjust your sketch

Step 5: Use the construction geometry to add relations or dimensions

- Sketch toolbar → Use 'Smart Dimension' or 'Add Relation' tools

The construction geometry helps position other sketch elements without creating solid features

Step 6: Finish the sketch

- Click 'Exit Sketch' on the Sketch toolbar

The sketch saves with construction geometry visible as dashed lines, guiding your model

Before vs After

Before

Sketch lines are solid and create physical edges in the model

After

Selected lines become dashed, acting as references without creating edges

Settings Reference

For Construction toggle

📍 Sketch toolbar

Switches selected sketch entities between normal and construction geometry

Default: Off

Display construction geometry

📍 View menu → Hide/Show → Sketches

Controls visibility of construction geometry in the sketch environment

Default: Show

Common Mistakes

Using construction geometry when solid edges are needed

Construction geometry does not create physical features, so the part will miss those edges

Only convert lines to construction when you want references, keep solid lines for actual features

Forgetting to toggle construction geometry back to normal when needed

This can cause missing features or unexpected model results

Double-check geometry type before finishing the sketch to ensure correct feature creation

Summary

Construction geometry creates reference shapes that do not affect the final model.

Use it to guide your design with helper lines, points, or curves.

Remember to toggle construction geometry on or off depending on whether you want physical features.