JRM Technologies proposes a new CUDA-based 3D thermal signature physics engine which combines real-time raytracing (photon-mapping) and localized temperature maps that together with new GPU shaders will better model the transient interactive coupling of dynamic thermal sources with affected 3D scene elements. To support this new physics engine, JRM proposes to leverage and extend its proven real-time atmospheric and irradiance physics libraries, fast 1D/3D thermal solvers, and real-time spectrally-customized Scenix/Optix-based photon mapping raytracer. This improved physics modeling will support localized, dynamic heat-source loading of nearby scene elements, and dynamic temporal solar loading/shadowing. The photon-mapping will realistically model complex local radiation exchange based on viewable surface areas and thermal sources, and couple that surface loading with localized finite difference thermal solvers to drive the temperature map updates over the simulation time. These maps will be updated and re-discretized on-the-fly as the dynamic sources move through the scene, while in an independent thread the new GPU signature shaders render corresponding localized transient signature effects from arbitrary points-of-view.