Stage structures, rigging geometry and load-path reasoning
Establish the real task and boundary
Event rigging supports equipment and structures under conditions that can expose crew, performers and the public. Begin with the actual design, responsibilities, manufacturer documentation, location and operating plan. A Swiss professional examination has stage and lighting specializations; this independent cross-disciplinary written practice is not a complete practical demonstration for either one. It does not authorize a lift, occupation beneath a load or a substitution for competent design and approval.
Follow the load path
Identify the supported equipment, connections, hoists, truss, suspension points, building structure and ground where relevant. Every relevant component and interface must be suitable for the actual direction, configuration and service conditions. Include appropriate accessory mass and dynamic effects rather than considering the payload alone. A uniform load and a concentrated load can produce different internal forces and deflections. Separate ratings for two load cases do not automatically establish permission for an arbitrary combined load.
Use a model with explicit assumptions
For an ideal symmetrical two-leg bridle carrying a static vertical force W, each leg at angle theta from the vertical has tension W divided by twice cosine theta. Flatter legs increase tension. Use consistent force units and avoid confusing mass with force. With more supports, unequal geometry or flexible structures, dividing total weight equally may be invalid; stiffness, center of gravity and actual constraints matter. Overturning concerns moments about the relevant edge, not merely whether the ballast weighs more than one component. A supplied calculation is not a complete stability check.
Preserve condition and control
Select and inspect suitable rated equipment using actual identification and discard criteria. Damage, missing identification, incompatible connectors or an unexpected load condition require a controlled stop and competent assessment rather than a visual guess. Keep required exclusion areas and agreed communications appropriate to the task. Stage weather plans must use the actual structure’s limits and predetermined actions; one universal wind threshold cannot safely cover every system. An inspection record or label does not prove that all support conditions and operational states are acceptable. Written mechanics and related basic-rigging exercises support understanding but do not establish current Swiss licensing, a live lift plan or complete specialist competence.