In SolidWorks, dimensions drive the model geometry; changing dimensions changes the shape of the model. You can relate dimensions to each other in equations.
- Open a sketch, sketch a rectangle, and dimension the rectangle.

- Modify the dimensions as needed while creating the sketch.

- Extrude a block base feature.

- Complete the feature to close the sketch and show the solid in shaded mode.

- To modify the block, edit the sketch, double-click a dimension and modify the value.

- Exit the sketch to rebuild the solid with the new dimension.
