The traditional approach to optical system engineering separates the scene, optics, and detector as static entities, optimizing the design to meet subsystem specifications of aperture, field size, encircled energy, read noise, dynamic range, and other electro-optical properties. The Scene-Based Sensor Model (SBSM) represents a different approach by simulating the scene, optics and detector as a cohesive model using commercially available optical ray-tracing software. The objects are modeled as temporally changing entities, with characteristics including reflectance, absorbance, fluorescence, and scattering. Likewise, the detectors are modeled with their properties of temporal noise, spatial non-uniformity, nonlinear gain, and offset drift. The end-to-end simulation produces "photons-to-bits" analysis applicable to a variety of optical systems. First results are illustrated with ray tracing simulation of moving fluorescent objects and laser induced breakdown spectroscopy.