What action does applying a geometric constraint achieve in a model?

Applying a geometric constraint in a model effectively restricts the movement of geometric entities. This means that when you impose constraints, you are explicitly defining relationships between components, such as their distances, angles, or orientations relative to one another. For example, if you set a parallel constraint between two lines, those lines will maintain their parallel relationship, irrespective of how you manipulate the model. This control is crucial in parametric design, ensuring that as dimensions and features are adjusted, the overall geometric integrity of the assembly or part remains consistent.

The other options, while relevant to aspects of modeling in Autodesk Inventor, do not accurately describe the primary function of geometric constraints. For instance, defining dimensions is more directly related to dimensioning tools rather than constraints, and although constraints can influence distances indirectly, their main goal is to manage the interrelationships rather than set the dimensions outright. Creating new geometric features pertains to the use of tools like extrude, revolve, or loft, which are separate from the act of constraining existing entities. Lastly, visualizing a model in 3D is concerned with rendering and viewing aspects of the design, which is not the primary outcome of applying geometric constraints.