This free interactive 3D model walks you through how a building's access-controlled doors are built — credential readers, the access control panel/controller, electric strikes and magnetic locks, request-to-exit (REX) devices, and door position switches. Click any door or device to see what it does and how it's wired. It's a visual learning tool for security designers, integrators, electricians, facility managers, and students learning electronic access control and life-safety egress.
The viewer covers the hardware that makes one controlled door work, repeated across the building:
• Credential readers — card, fob, PIN keypad, or mobile/biometric readers mounted on the secure side of the door. • Access control panel / controller — the field controller that reads credentials, checks them against permissions, and energizes the lock. • Locking hardware — electric strikes and electromagnetic (maglock) locks, the two most common door locks. • Request-to-exit (REX) device — motion sensor or push bar that signals a valid exit so the system doesn't log a forced-door alarm. • Door position switch (DPS) — a magnetic contact that tells the system whether the door is open, closed, or held open too long. • Fail-safe vs fail-secure wiring — how the lock behaves when power is lost, which drives egress and life-safety code compliance.
When someone presents a credential, the reader sends it to the access control panel. The panel checks the credential against an access schedule (who, which door, what time) and, if valid, releases the lock for a few seconds so the door can open. A request-to-exit device releases or bypasses the lock for people leaving from the secure side, and the door position switch confirms the door actually opened and re-closed. The same panel monitors for forced-open and door-held-open events and logs every transaction. Crucially, locks are configured fail-safe (unlocks on power loss) or fail-secure (stays locked on power loss) depending on the door's egress and fire-life-safety requirements — maglocks are always fail-safe and must release on fire alarm and loss of power.
1. Drag to orbit the building, scroll to zoom, and pan to move around. 2. Click a door or device to highlight it and read what it does and how it connects to the controller. 3. Trace the signal path (reader → panel → lock) and the egress path (REX → lock release, DPS monitoring) to see how a controlled opening is wired end to end.
A fail-safe lock unlocks when it loses power — used where the door must allow egress or release on a fire alarm (electromagnetic locks are always fail-safe). A fail-secure lock stays locked when it loses power, keeping the opening secure during an outage. The choice is driven by the door’s egress route and life-safety code, not just by security preference.
A request-to-exit device — usually a motion sensor over the door or a switch in the exit hardware — tells the access control panel that someone is legitimately leaving from the secure side. It releases or bypasses the lock for egress and prevents the system from logging a normal exit as a forced-door alarm.
An electric strike replaces the strike plate and can be fail-secure or fail-safe, working with standard latching door hardware so the door stays mechanically latched. A magnetic lock (maglock) is a powered electromagnet that holds the door shut and is always fail-safe — it releases on power loss and must release on fire alarm — so it requires additional egress devices to meet life-safety code.
A credential is what a person presents to prove they’re authorized — a proximity card, key fob, PIN, mobile phone, or biometric. A reader is the device at the door that captures the credential and passes it to the controller. Modern systems increasingly use OSDP and encrypted smart cards or mobile credentials instead of legacy Wiegand and low-frequency prox.
Egress codes require that people can always leave a building freely, even during a power failure or fire. Controlled doors on egress paths must allow free exit (via REX hardware, panic bars, or fail-safe release) and electromagnetic locks must release on fire-alarm activation and loss of power. Local building and fire codes, plus standards like UL 294, govern how access control hardware can be applied to egress doors.