Which command is specifically used to create symmetric instances of a solid body?

The command used to create symmetric instances of a solid body is the Mirror Part command. This function allows users to create a mirrored copy of a complete body across a specified plane. By utilizing this command, parts can be duplicated symmetrically, which is particularly useful in design workflows that require symmetrical components, such as in mechanical designs or assemblies.

The Mirror Part command ensures that any modifications to the original body can be reflected in the mirrored instance, maintaining design integrity. This capability is essential for efficiently creating complex geometries that are often seen in symmetrical designs without needing to model each side of the body separately.

While other commands like Mirror Face or Mirror Feature also deal with mirroring, they do not create complete solid bodies with symmetry across a whole part, which is the primary goal in this scenario. Extract Geometry, on the other hand, is used for capturing existing geometry for reference or secondary features but does not perform any mirroring operations.