The measurement problem is the fundamental puzzle of quantum mechanics: why does a quantum system evolve deterministically under the Schrödinger equation between measurements, yet produce a single definite outcome when measured? Why does the wavefunction appear to collapse? And what constitutes a measurement? In the canvas model, measurement is not an additional postulate. It is a threshold crossing event. A quantum system is a closed wave—a bound state formed by wave intersection. A measurement apparatus is another closed wave. When the quantum system and the apparatus interact, their combined wave amplitudes may exceed the threshold for voxel nucleation. The crossing of this threshold transforms the deterministic, continuous wave dynamics into a discrete, stochastic event: the registration of a definite outcome. What this paper provides: · A physical mechanism for wavefunction collapse. Collapse is not instantaneous or non-unitary. It is the formation of a new closed wave at the moment of threshold crossing. The transition from a superposition to a single outcome occurs over a finite timescale (set by the threshold dynamics), with the open wave components that do not cross threshold being depleted. The original system wave may be absorbed or continue with reduced amplitude.· A derivation of the Born rule from threshold probabilities. The probability that a wave component crosses threshold scales as the square of its amplitude. For a quantum state |\psi\rangle = \sum_i c_i |a_i\rangle, the probability of obtaining outcome a_i is P(a_i) = |c_i|^2. The Born rule is not an axiom—it follows from the ratio of threshold crossing probabilities.· An elimination of the Heisenberg cut. The classical-quantum boundary is the measurement threshold T_{\text{meas}} itself. Systems with combined amplitude below threshold evolve unitarily (quantum). Systems at threshold undergo probabilistic transitions (measurement). Systems above threshold are classical (definite outcomes). No arbitrary division between observer and observed is required. The von Neumann chain stops at the first threshold crossing, typically the apparatus.· Resolutions of famous paradoxes. Wigner's friend: measurement is not relative to an observer—it is relative to a threshold. Both Wigner and his friend are correct within their own threshold domains. Schrödinger's cat: the Geiger counter registering decay is a threshold crossing; the cat is never in a superposition. The quantum Zeno effect: frequent threshold crossings deplete the wave amplitude available for transitions, slowing evolution naturally.· A comparison with existing interpretations. The canvas model is compared with Copenhagen (collapse postulated), Many-Worlds (no collapse, Born rule derived from decision theory), Bohmian mechanics (non-local hidden variables), objective collapse models (new physical constants), and QBism (epistemic wavefunction). The canvas model is unique in deriving both collapse and the Born rule from the same underlying dynamics without introducing new postulates beyond those already required for the unification of forces. Why this matters: The measurement problem has persisted for nearly a century. The canvas model provides a unified account of measurement derived from the same primitives that generate the forces, particles, and spacetime structure of our universe. Measurement is not a mystery added to physics. It is physics, operating at the threshold. No additional postulates, hidden variables, or many worlds are required. Keywords: measurement problem, wavefunction collapse, Born rule, threshold crossing, closed wave, canvas model, Heisenberg cut, Wigner's friend, Schrödinger's cat, quantum Zeno effect