| Material Complexity | CPU (AVX-512) | GPU (NVIDIA RTX) | Bottleneck | |---------------------|---------------|------------------|-------------| | Simple Lambertian | 100% | 85% | Thread sync | | GGX + 2 textures | 100% | 210% (faster) | Texture fetch latency | | SSS + displacement | 100% | 45% (slower) | Divergent threads |
For conductors (metals), V-Ray uses the ( \tilden = n + ik ), where ( k ) is the extinction coefficient: vray materials
[ f_oren = \frac\rho\pi \left( A + B \cdot \cos(\phi_i - \phi_o) \cdot \sin(\alpha) \cdot \tan(\beta) \right) ] | Material Complexity | CPU (AVX-512) | GPU
[ G_Smith(l,v) = \chi^+ \left( \frac2 (n \cdot l)(n \cdot v)(n \cdot v) \sqrt\alpha^2 + (1-\alpha^2)(n \cdot l)^2 + (n \cdot l) \sqrt\alpha^2 + (1-\alpha^2)(n \cdot v)^2 \right) ] V-Ray distinguishes materials via the Fresnel equation , not a binary metallic flag. For dielectrics (glass, wood, plastic): BRDF Microfacet Theory
Novel contribution: V-Ray 5+ introduced a that allows artists to bypass IOR physics by directly encoding reflectivity per angle, though this breaks energy conservation unless carefully managed. 4. Advanced Sub-Surface Scattering (SSS) Approximation For materials like marble, wax, or skin, V-Ray implements the BSSRDF (Bidirectional Surface Scattering Reflectance Distribution Function). The VRayFastSSS approximates the dipole diffusion model:
A Comprehensive Analysis of V-Ray Material Models: Physically-Based Rendering, BRDF Microfacet Theory, and Stochastic Texture Evaluation