1. What this tool does
This calculator builds a simplified rigid-body model of a freestanding entertainment structure. You tell it what supports the structure on the floor, how much each part weighs, and where those weights are located. It combines those inputs into a center of gravity and compares the gravity line with the support boundary.
2. Start with the support
Enter the effective base footprint, base height, and base weight. The datum never moves: the center of the support footprint at floor level is X = 0, Y = 0, Z = 0. A 36 in tall block therefore occupies Z = 0 through Z = 36 in.
3. Describe the structure
Enter the overall height measured from the floor. Add truss, pipe, masts, sidearms, or other straight pieces as Structural Members. A uniform member is represented by its start and end points and its weight acts at the midpoint.
4. Add equipment, loads, and ballast
Add lights, speakers, scenic pieces, ballast, motors, and other concentrated weights. For each item, enter its installed weight and the approximate XYZ location of its center of gravity.
5. Verify the pictures before trusting the numbers
Use Top, Front, and Side views as an input check. Ask: does this picture resemble what I intended to model? Is the base the right size and height? Are structural members sitting where they physically sit? Are loads on the correct side and at the correct elevation? Use Expand for a larger in-page view or Pop Out for a separate read-only window that stays live while you edit the main calculator.
6. Read the inherent-stability advisory
Total weight and combined CG describe the modeled mass. Critical support margin is the remaining horizontal distance to the controlling support edge. Critical tip angle is the rigid-body tilt angle at which the CG gravity line reaches that edge. This version applies a calculator advisory color to that angle: RED at or below 0°, ORANGE above 0° and below 15°, YELLOW from 15° to below 30°, and GREEN at 30° or greater. These are calculator advisory thresholds, not ANSI/ESTA design criteria. Critical restoring moment and horizontal force to theoretical tip remain supporting physical quantities.
7. Use equivalent horizontal force as a teaching comparison
The tool can divide the restoring moment by a selected force application height. This tells you the idealized horizontal static force at that height that would create an equal overturning moment. It is not a real-world pull-test rating or allowable load.
8. Add wind only when appropriate
Wind is the current applied overturning-load case used by the four-color Overturning Stability rating. The rating compares the directional restoring moment with the entered wind overturning moment. If no overturning load is active, the rating remains NOT RATED rather than showing a misleading GREEN result. Speed Screening remains intentionally simplified; Direct Design Pressure is available when an appropriate pressure has been established elsewhere.
9. Explore tipping geometry
The Tipping Geometry Visualization rotates the assembly about the critical ground-contact edge. The CG travels with the structure, but the gravity line remains vertical. When that line passes through the pivot, the idealized rigid-body static threshold has been reached.
10. Review warnings
A warning means an input deserves a second look, not necessarily that the model is impossible. For example, an endpoint above the entered overall structure height may be intentional, or it may be a typo.
11. Save, export, and print
Save Locally stores the current project in this browser. Export JSON creates a portable project file. Print Analysis produces a report-oriented view that can also be saved as PDF.
12. What this tool does not determine
It does not determine member strength, truss allowable loading, buckling, connection or fastener capacity, anchorage, floor capacity, sliding resistance, dynamic or impact loads, seismic effects, manufacturer restrictions, code applicability, or engineering approval. Those can govern before this simplified tipping model does.
