In rigging, what is the term for an object that maintains its shape while under load?

The term that describes an object that maintains its shape while under load is "rigid." A rigid material does not deform significantly when stress is applied, meaning it retains its original shape even when subjected to heavy loads. This characteristic is crucial in rigging because it ensures the stability and predictability of the structure or system being used to lift or support heavy objects.

In rigging practices, using rigid materials—such as certain metals or composites—helps ensure that the equipment can safely support loads without bending or succumbing to temporary deformation that might occur in more flexible materials. This reliability enhances safety and performance during lifting operations, as it minimizes the risk of failure that could arise from unexpected changes in shape or structure.

Other terms such as elastic and plastic refer to materials that do deform, either returning to their original shape after the load is removed (elastic) or permanently changing shape (plastic). Ductile pertains to a material's ability to stretch and deform under tensile stress before breaking, which isn't the same as maintaining shape under load. Thus, "rigid" is the appropriate term that accurately encapsulates the desired quality for maintaining shape under load in the rigging context.