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Stage Sightline Calculator
Check the height of a straight audience-to-target sightline at an intervening obstacle and export the clearance.
Eye height (m): 0.1–5; Target point height (m): 0–50; Eye to target distance (m): 0.2–1000; Eye to obstacle distance (m): 0.1–999; Obstacle height (m): 0–50
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Stage Sightline Calculator
Eye height (m): 1.2 Target point height (m): 2 Eye to target distance (m): 20 Eye to obstacle distance (m): 10 Obstacle height (m): 1.5
- Sightline height at obstacle (m)
- 1.600000
- Signed clearance (m)
- 0.100000
- Minimum target height to graze (m)
- 1.800000
All heights use one common horizontal floor datum. Let E be eye height, T target point height, D horizontal eye-to-target distance, x horizontal eye-to-obstacle distance and H obstacle height. Sightline height = E + (T−E)x/D; clearance = sightline height−H; minimum target height for grazing clearance = max(0, E+(H−E)D/x). Example: E=1.2, T=2, D=20, x=10, H=1.5 m gives 1.6 m line height and +0.1 m clearance. Require 0<x<D. Positive clearance clears the modeled obstacle, zero grazes it, negative is obstructed. This point model excludes heads, movement, depth, slopes and sightline margins; it is not seating, accessibility or structural certification. Verify actual viewing positions on site.
Methodology
How it works
All heights use one common horizontal floor datum. Let E be eye height, T target point height, D horizontal eye-to-target distance, x horizontal eye-to-obstacle distance and H obstacle height. Sightline height = E + (T−E)x/D; clearance = sightline height−H; minimum target height for grazing clearance = max(0, E+(H−E)D/x). Example: E=1.2, T=2, D=20, x=10, H=1.5 m gives 1.6 m line height and +0.1 m clearance. Require 0<x<D. Positive clearance clears the modeled obstacle, zero grazes it, negative is obstructed. This point model excludes heads, movement, depth, slopes and sightline margins; it is not seating, accessibility or structural certification. Verify actual viewing positions on site.
Method and assumptions documented by Techrider.live
2026-10-16
Frequently asked questions
Does positive clearance guarantee a good view?
No. It only clears a single obstacle at one modeled point. Include people, movement and a practical margin when planning, then verify the real venue. Distances are horizontal and every height must share the same datum.