Definition and Analysis of the Modulus Length: Based on the Envelope Interface Framework

Within the Envelope Interface framework, the Modulus Length is defined as the product of the minimum length and the maximum frequency of the observer's envelope layer. It is not an absolute constant, but a local reading jointly determined by envelope geometry and external coupling. This paper proves that when the ruler of the envelope surface scales synchronously with the world, the modulus length appears as a stable constant; however, once the envelope surface breathes (fluctuations in b(t)) or external coupling changes, the modulus length drifts. The observer generates the world self-similarly along the envelope surface through 90° phase flips, thus he can only read a locally stable modulus length and cannot perceive its conditionality. Mainstream physics welds the modulus length (the speed of light c) as an absolute premise; WQT points out that this premise itself is the product of projection-layer readings.