FX:Scape Tools
Bridle Calculator
Start with four simple measurements to solve a two-leg bridle, see the geometry and forces immediately, then open Advanced Analysis when you need full 3D coordinates, reactions, capacities, and detailed rigging information.
Bridle Setup
Start with what you know
Add leg capacities (optional)
Enter the applicable working load limit (WLL) for each complete leg only if known. Do not substitute minimum or ultimate breaking strength.
Live Geometry
Your bridle
Bridle Analysis
What this setup produces
Advanced Analysis
Define the full bridle
Live Results
Bridle analysis
Vector Diagram
Geometry & forces
A1 / Leg 1
Reaction & geometry
A2 / Leg 2
Reaction & geometry
Analysis assumptions: Unless replaced in Advanced Analysis, A1 and A2 are modeled at equal elevation, the bridle is modeled in a single vertical plane, Y offset is zero, and the applied load is vertical at P. Unknown capacities are not assumed acceptable.
Method: Two-leg static equilibrium solved from 3D unit vectors at P. Leg-force and reaction components are reported in the project coordinate system. Any nonzero equilibrium residual is reported rather than hidden.
Leg Builder
Plan a finished leg assembly
Method & References
What the calculator is doing
Donovan notation
The calculator follows Harry Donovan’s bridle terminology: A1/A2 for anchorages, P for the applied-force point, FL for force along a leg, FV/FH for vertical and horizontal components, and DL/DV/DH for leg geometry.
3D equilibrium
Each leg is converted to a unit vector from P toward its anchorage. The engine solves the two leg tensions that best balance the applied gravity force. If the three vectors cannot close, the unresolved residual is displayed and the geometry is flagged rather than treated as valid.
ANSI E1.56-2026
E1.56 addresses stationary permanent rigging support points attached to permanent facility structure. It does not turn an arbitrary bridle calculation into an approved structural attachment. Point capacity, lateral-force acceptance, connection method, hardware, and venue/qualified-person requirements remain separate checks.
Advisory language
Geometry warnings are intentionally advisory. The app does not claim that a particular included angle is universally “ANSI safe.” Capacity checks only compare calculated forces with ratings explicitly entered by the user.
Standards & Analysis References
Standards context
This tool is intended to support understanding and preliminary planning of two-leg bridles in entertainment rigging. Relevant references include Harry Donovan, Entertainment Rigging: A Practical Guide for Riggers, Designers, and Managers for bridle geometry and force-component methodology, and ANSI E1.56-2026, Entertainment Technology — Rigging Support Points where its scope applies to stationary permanent rigging support points attached to permanent facility structure. Other standards, manufacturer requirements, engineered venue criteria, building codes, and project-specific requirements may also apply.
The application does not reproduce applicable standards, determine code applicability, approve structural attachments, or certify compliance. Geometry classifications and advisory indicators are general guidance for interpreting calculated results and are not ANSI/ESTA pass/fail criteria, engineering approval, or a determination of rigging safety. Users are responsible for verifying applicable standards, support-point restrictions, lateral-force acceptance, component ratings, hitch/configuration effects, manufacturer requirements, and project-specific conditions.
Important Notice
Disclaimer & Limitation of Use
This application is provided solely as an informational, educational, and preliminary planning aid. All calculations, classifications, illustrations, and results are mathematical estimates derived from dimensions, locations, loads, ratings, assumptions, and other information entered by the user. Actual field conditions may differ materially from the modeled conditions. No representation, warranty, certification, approval, or guarantee, express or implied, is made regarding the accuracy, completeness, reliability, suitability, structural adequacy, safety, code compliance, or fitness for any particular purpose of any calculation, result, classification, display, or information produced by this application.
This application does not constitute engineering services, structural design, professional advice, inspection, testing, approval, certification, or a determination that any bridle, support point, structure, component, connection, or installation is suitable for loading, operation, or use. It is not a substitute for manufacturer instructions and limitations, engineered drawings, venue requirements, site-specific evaluation, applicable laws, codes or standards, competent inspection, or review by an appropriately qualified or licensed professional where required.
Actual rigging performance may be affected by conditions that are not modeled, are simplified, or are outside the scope of this application, including but not limited to structural member and connection capacity, allowable horizontal or lateral loading, anchorage and basket geometry, sling construction and hitch effects, hardware orientation and side loading, bending, D/d effects, component compatibility, dynamic, impact or transient loads, movement, vibration, load distribution, installation tolerances, deterioration, environmental conditions, manufacturer restrictions, and changes occurring after the analysis.
Any favorable, positive, or color-coded result indicates only the mathematical outcome of the specific modeled assumptions and entered conditions. No result should be interpreted as a representation or guarantee that a bridle is safe, code compliant, engineered, approved, or suitable for a particular application. The user remains solely responsible for verifying all inputs, assumptions, field conditions, governing requirements, component ratings, support-point limitations, and the applicability of the results, and for obtaining appropriate professional review before relying on this application for installation, operation, or life-safety decisions.
Use of this application and reliance on any result or information produced by it are at the user’s own risk.
© 2026 FX:Scape LLC. All Rights Reserved.