V-Ray Tip: Energy-Preserving Material Workflow for V-Ray

Set up materials to conserve energy so reflection, refraction, diffuse, and coat never add more light than they receive. This prevents blown highlights, fireflies, and unstable GI.

• Use physically based materials: Prefer VRayMtl/Physical Material. With Fresnel enabled and realistic IOR, V-Ray automatically balances reflection vs. diffuse/refraction.
• Rely on Fresnel, not white reflection: Keep Reflection color moderate (avoid pure white) and let IOR (1.3–1.6 for dielectrics) control intensity. For metals, use the metalness workflow instead of colored diffuse.
• Keep albedo in range: Avoid overly bright diffuse/base color. As a rule of thumb, keep most dielectrics under ~0.8 linear (~sRGB 204). Extremely bright albedos amplify GI and noise.
• Prefer GGX BRDF: GGX is energy preserving and produces realistic tails in highlights. Combine with plausible roughness to avoid “mirror-like” overbright responses.
• Use the built-in Coat: The Coat layer in VRayMtl is energy-preserving. If you must stack layers, avoid additive blends; normalize weights or use VRayBlendMtl in normal (non-additive) mode.
• Balance refraction and reflection: High refraction plus high reflection breaks realism. With Fresnel on, reflection boosts at grazing angles while transmission dominates at normal incidence—don’t fight it.
• Thin vs. solid objects: For thin sheets (leaves, plastics), use thin-walled/translucency modes to avoid double energy from both refraction and diffuse.
• Emission is additive energy: VRayLightMtl and emissive maps act like light sources. Use realistic cd/m² or intensity values, keep bloom/glow for post, and avoid compensating with extreme HDR texture levels.
• Texture correctness: Keep linear workflow consistent. Set correct color space/gamma per map type (color vs. data maps like roughness/metalness/IOR) to prevent unintended energy spikes.
• Troubleshooting cues: If you see persistent fireflies, blown edges, or GI “light leaks,” look for additive material layers, overbright diffuse, colored specular on dielectrics, or reflection set to pure white.

Practical setup checklist:

• Enable Fresnel reflections; lock reflective IOR to refraction IOR for dielectrics.
• Dielectrics: Diffuse/base carries color; specular remains near-white, controlled by IOR.
• Metals: Use metalness workflow; base is near black, color lives in the specular.
• Prefer the VRayMtl Coat over stacked reflective layers.
• Keep roughness physically plausible; ultra-sharp coats stack energy quickly.
• Avoid additive comp of multiple reflective AOVs; use proper LightMix/Render Elements and normalize in comp.

Performance benefits:

• Faster noise convergence—less extreme brightness variance for the sampler to resolve.
• More stable GI—no over-energized bounces causing flicker in animation.
• Predictable compositing—beauty and AOVs align without surprise “extra light.”

Need licenses, upgrades, or guidance on best practices? Explore V-Ray solutions at NOVEDGE, or reach out to the NOVEDGE team for tailored advice on pipeline-friendly, energy-conserving material workflows.

You can find all the V-Ray products on the NOVEDGE web site at this page.