🎯 Introduction
Before you create anything in 3D, you must first draw it in 2D.
That’s the role of Sketch — it’s the foundation of every part in SolidWorks.
Think of it like a blueprint that defines the shape and size of your object before it becomes solid.
🧭 What Is a Sketch?
A Sketch in SolidWorks is a 2D drawing that you create on a plane (like a flat surface).
It can contain lines, circles, rectangles, arcs, points, and dimensions.
Every 3D model you’ll ever make — from a simple cube to a car engine — starts as a sketch.
🔹 Example:
When you draw a rectangle on the Top Plane, you are making a sketch.
When you extrude it (using Extruded Boss/Base), that rectangle becomes a 3D solid block.
📐 Where Do Sketches Live?
Sketches are always created on a plane.
By default, SolidWorks gives you three base planes:
- Top Plane → view from above
- Front Plane → front view
- Right Plane → side view
You can also create your own custom planes later for more complex shapes.
⚙️ Main Sketch Tools
Here are the tools we use most often in Sketch mode:
| Tool | Function |
|---|---|
| ✏️ Line | Draws straight lines between two points |
| ⭕ Circle / Arc | Draws circles or curved edges |
| ◼️ Rectangle | Draws rectangular or square shapes |
| 📏 Smart Dimension | Defines exact distances, angles, or diameters |
| 🎯 Relations (Constraints) | Keeps geometry connected (e.g., horizontal, vertical, equal length, tangent, etc.) |
🔒 Fully Defined vs Under Defined
When your sketch is fully defined, it means every element (lines, circles, etc.) has a clear position and size.
SolidWorks shows this in black color.
If it’s still blue, it means some parts are “free” or not dimensioned yet — this can cause problems later when extruding.
✅ Always aim for Fully Defined sketches before creating 3D features.
🧩 Sketch vs Feature
This is a big confusion for beginners:
- Sketch = 2D drawing (the “idea”)
- Feature = 3D operation (the “action” that transforms it)
👉 Example:
Draw a circle → that’s a Sketch.
Use Extruded Boss/Base → now it becomes a 3D cylinder (that’s a Feature).
💡 Conclusion
In SolidWorks, mastering Sketch means mastering the foundation of design.
Once you understand how to control lines, dimensions, and relations, you can build anything — from a simple plate to a complex mechanical system.
