Envelope Interface: Definition, Geometric Properties, and Physical Significance

Within the frameworks of World Quantum Theory (WQT) and Frequency World Theory (FWT), this paper defines and analyzes the Envelope Interface — a closed three-dimensional perceptual surface formed by a Rūpa-Skandha Element specifying the fundamental parameters, using the Survey Line Spiral as the constructive structure, and shaped by a coupled vortex. The Envelope Interface is not a material entity, but the geometric form of the perceptual interface. This paper presents its generation conditions, geometric definition, breathing frequency, physical implications, and its relationship with the observer anchor, providing a foundation for its application in spatial perception, quantum measurement, and consciousness research. Keywords: Envelope Interface, Survey Line Spiral, Rūpa-Skandha Element, vortex, World Quantum Theory, perceptual interface, phase-locking, breathing frequency