PressureBlush: Real-Time Blanching and Hyperemia Shading from Neural Deformation Signals

We present PressureBlush, a real-time system for blanching and hyperemia during self-contact. Our approach reinterprets the output of a neural deformation network as an implicit pressure signal, producing a physiologically motivated appearance response.

At the geometry level, we construct a customized training dataset and train a neural deformation network to predict self-contact-specific deformation. At the appearance level, we interpret the trained network's per-vertex output as a pressure proxy and resolve it into central blanching and peripheral hyperemia. The resulting response has distinct temporal dynamics, reflecting the asymmetry between immediate capillary occlusion under pressure and delayed reactive reddening after release.

The appearance response is evaluated entirely in shader, without additional simulation, precomputed textures, or artist-authored masks, enabling real-time contact-induced appearance change from learned deformation signals alone.

PressureBlush has two stages: data generation for learning contact-isolated deformation, and runtime appearance synthesis from the learned signal. Paired Houdini Otis tissue simulations, one with self-collision and one without, yield a contact-isolated residual that trains Unreal Engine's ML Deformer (Neural Morph Model). At runtime, the predicted corrective displacement is reinterpreted relative to the LBS mesh as pressure signals.

The corrective displacement is projected onto the surface normal to give inward (P_in) and outward (P_out) pressure. Contact Response Synthesis resolves these into temporally phased responses: an Impulse phase (a thin whitening band at the contact edge), a Sustained phase (blanch at the compressed centre, hyperemia around it), and a Residual phase (lingering peripheral redness after release). Hyperemia is composited first and blanching on top, so doubly-affected pixels read pale, consistent with capillary occlusion dominating reactive reddening.

PressureBlush combines self-contact-specific deformation with the corresponding color response, making contact visually legible and physically convincing through both shape and color.