Effective 2D Sketching Techniques
The 2D sketch is the foundational step for all 3D geometry in SolidWorks. Effective sketching relies on defining the geometry precisely using dimensions and geometric relationships, which prevents unintentional changes and errors in the 3D model.
1. Smart Dimension
Function: The primary tool used to control the size and location of sketch entities.
Concept: It automatically detects the type of dimension needed (linear, radial, angular) based on what you click.
Effective Use: Dimensions should be placed from a fixed point (like the Origin or a construction line) and should reflect the part's design intent (e.g., placing a dimension from a key mounting hole to the edge).
2. Relations (Geometric Relations)
Function: Constraints that define the geometric relationships between sketch entities.
Concept: Relations are often more powerful than dimensions because they enforce permanent design intent. For example, making two lines Equal ensures they always have the same length, even if one is dimensioned.
Common Relations:
Horizontal/Vertical: Ensures a line is perfectly horizontal or vertical.
Perpendicular/Parallel: Defines the relationship between two lines.
Tangent: Ensures a line or arc smoothly meets another curve.
Coincident: Locks a point onto a line or curve.
Equal: Forces two entities (e.g., circles or line segments) to have the same size.
3. Using Planes (Front, Top, Right, and Custom Planes)
Function: Defines the 2D surface upon which the sketch will be created.
Concept: Every new part starts with three default Reference Planes (Front, Top, Right). Choosing the correct plane is crucial:
The first sketch for the main feature should typically be on one of these default planes, preferably the one that minimizes subsequent work.
The intersection of these planes is the Origin, which should be used as the anchor point for your first sketch to make it fully defined and stable in 3D space.
Custom Planes: Later, you may need to create a new plane (Reference Geometry > Plane) offset from or angled to an existing surface or plane for complex features.
Key Goal: Your goal for every sketch is to achieve Fully Defined status (lines turn black), meaning it cannot be unintentionally dragged or resized. This is achieved by using a combination of Smart Dimensions and Relations.
| Main | SolidWorks, 2D Sketching, 2D Sketching, Sketching Techniques |
| Level/Target Group | Newbie, Basic, Fully Defined |
| Specific commands | Smart Dimension, Relations, Plane, Reference Plane, Origin, Black Sketch |
| relationship | Geometric Relations, Coincident, Tangent, Parallel, Perpendicular, Equal |
| language | English, English Tutorial, Thai |
Figure 1: Choosing the Right Sketch Plane
Image caption: Shows the default reference planes (Front, Top, Right Plane) in SolidWorks with the Origin point and recommends starting the sketch on the appropriate plane.
Image text: "SOLIDWORKS FOR BEGINNERS", "1. CHOOSING THE SKETCH PLANE", "FRONT PLANE", "RIGHT PLANE", "TOP PLANE", "ORIGIN", "START SKETCH ON A PLANE"
Figure 2: Using Smart Dimension for Size & Position
Image caption: Shows how to use Smart Dimension to define the size and position of shapes in a sketch, making the sketch Fully Defined (lines in black).
Image text: "SOLIDWORKS FOR BEGINNERS", "2. SMART DIMENSION - SIZE & POSITION", "FULLY DEFINED SKETCH (BLACK)", "CONTROLS SIZE & LOCATION"
Figure 3: Applying Geometric Relations (Constraints)
Image Caption: Demonstrates the use of Geometric Relations such as Parallel and Tangent to define the geometric relationship between lines and arcs in a sketch.
Image text: "SOLIDWORKS FOR BEGINNERS", "3. APPLYING GEOMETRIC RELATIONS", "PARALLEL RELATION: FORCES LINES TO STAY PARALLEL", "TANGENT RELATION"
Figure 4: Fully Defined Sketch - The Goal
