What Does Fully Defined Mean in SolidWorks?

In SolidWorks, the term “fully defined” refers to the state of a sketch where all the sketch entities and dimensions are constrained. A fully defined sketch is essential for accurate modeling and ensuring that your design behaves as expected.

Why is it important to have a fully defined sketch?

Having a fully defined sketch is crucial because it eliminates any ambiguity in your design. It defines the relationships and constraints between different sketch entities, ensuring that they maintain their intended positions relative to one another. This level of control is necessary when creating complex 3D models.

How to create a fully defined sketch?

To create a fully defined sketch in SolidWorks, you need to apply appropriate constraints and dimensions to all the sketch entities. Constraints restrict the movement or alignment of entities, while dimensions specify their size or position.

Here’s how you can achieve full definition in your sketches:

1. Create your sketch: Start by selecting a plane or surface on which you want to create your sketch. Use the Sketch toolbar or right-click on the selected plane/surface and choose “Sketch” from the context menu.

2. Add sketch entities: Use tools like lines, arcs, circles, rectangles, etc., to draw your desired geometry.

3. Apply dimensions: Dimensions define the size or position of your sketch entities.

Click on the “Smart Dimension” tool from the Sketch toolbar and select two points or edges that you want to dimension. Enter the desired value in the dimension dialog box.

4. Apply constraints: Constraints ensure that your entities maintain their intended relationships with each other. Use tools like “Coincident,” “Parallel,” “Perpendicular,” etc., from the Sketch toolbar to apply constraints between different entities.

5. Check for under-defined entities: After applying dimensions and constraints, SolidWorks automatically calculates the remaining dimensions required to fully define the sketch. If any entities are still under-defined, they will appear in blue color.

6. Apply missing dimensions or constraints: Select the under-defined entities and apply additional dimensions or constraints until all sketch entities turn black, indicating that they are fully defined.

  • Common constraints:
    • Coincident: Forces two points or vertices to share the same position.
    • Parallel: Ensures that lines or edges remain parallel to each other.
    • Perpendicular: Forces lines or edges to intersect at a 90-degree angle.
    • Tangent: Makes arcs or circles tangent to other entities.
  • Common dimensions:
    • Linear dimension: Specifies the length between two points or edges.
    • Diameter dimension: Measures the diameter of arcs or circles.
    • Angular dimension: Defines the angle between two lines or edges.

Tips for working with fully defined sketches

Once you have a fully defined sketch, it’s important to keep a few things in mind:

Avoid over-constraining

While constraints are necessary for full definition, it is possible to over-constrain your sketch. Over-constraining can lead to conflicts and make it difficult to modify your design later. Be mindful of adding only essential constraints that accurately represent your design intent.

Edit with caution

When editing a fully defined sketch, be aware that modifying one dimension or constraint could affect others. SolidWorks tries to maintain the relationships between sketch entities, so changing one parameter might lead to unexpected changes in other parts of the sketch. Review your changes carefully and make adjustments as needed.

Usefully defined sketches for better parametric modeling

Fully defined sketches are the foundation for creating parametric models in SolidWorks. By establishing precise relationships between sketch entities, you can easily modify your design later by changing dimensions or constraints. This flexibility is especially valuable when working on iterative design processes or accommodating design changes.

In conclusion, understanding what it means to have a fully defined sketch in SolidWorks is vital for accurate and reliable modeling. By applying appropriate dimensions and constraints, you can ensure that your sketches are fully defined and ready for creating robust 3D models.