CG Rendering With V-Ray II

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Forget the stupor of Mental Ray and get yourself a real 3D rendering engine in Chaos Group’s V-Ray.

If you’re thinking about crossing over, let me save you the time it took me to do my research and offer up my updated work flow configurations.

Configuring 3DS Max Gamma and LUT

  1. In 3DS Max go to Customize > Preferences > Gamma and LUT (Tab) make sure “Enable Gamma/LUT Correction” is checked.
  2. In Display set Gamma to 2.2
  3. In Bitmap Files set Input Gamma to 2.2 [1] and set Output Gamma to 1.0.

Configuring 3DS Max Environment and Effects

  1. In 3DS Max go to Rendering > Environment and set Exposure Control to “< No Exposure Control >.”

Configuring the V-Ray renderer

  1. In the Render Scene Dialogue > Common (Tab) > Render Output uncheck Rendered Frame Window [2].
  2. Assign V-Ray as the current rendering engine (with the default V-Ray settings).
  3. In Frame Buffer (Rollout) check Enable built-in Frame Buffer.
  4. In V-Ray (Tab) > Global Switches (Rollout) select Default Lights to “off”
  5. In Image sampler (Antialiasing) (Rollout), switch the image sampler Type to Adaptive DMC.
  6. In Environment (Rollout) check GI Environment (skylight) override. [3] In Adaptive DMC image sampler (Rollout) Leave the Min. subdivs at 1and set the Max. subdivs to 100 (one hundred).
  7. In Color Mapping (Rollout), switch the Color Mapping Type to Reinhard, Burn Value to .8 and Gamma to 2.2. Make sure that the Clamp output and Sub-pixel mapping options are unchecked.
  8. In Indirect illumination > Indirect illumination (GI) (Rollout) Turn GI on, set the Primary GI engine to Irradiance map (As an alternative, you could set the Primary GI engine to Brute force [4].) and set the Secondary GI engine to Light cache. Set both multipliers to 1.0.
  9. If the Primary GI engine is set to Irradiance map, in Irradiance map (Rollout) select a preset (Medium) or configure your desired quality. In options check Show calc. phase (optional).
  10. In Light cache (Rollout) set the light cache Interp. samples to 5, turn on the “Use light cache for glossy rays” option to speed up glossy reflections, and check Show calc. phase (optional).
  11. In Settings (Tab) > DMC Sampler (Rollout) set the Adaptive amount parameter to 1.0. Set the Noise threshold to 0.02 [5] [6].

Configuring to Control Render Quality vs. Render Time

  • In Settings (Tab) > DMC Sampler (Rollout) adjust the DMC Noise threshold [5].
  • Adjust the Light cache Subdivs (usually values from 1000-5000).
  • Turn on or off reflective/refractive GI caustics as needed.
  • You may want to adjust the render region (bucket) size for faster feedback.
  • Adjust Reflect interpolation of glossy materials in the material editor (-1,-1 or -1,-3, the latter if it is an animation). For still images check “use interpolation” to get better rendering times but make sure that it is unchecked if you are using glossy reflections in an animation or they will flicker and blink.
  • Avoid using Photometric lights and use Vray Lights as much as possible.
  • If the Primary GI engine is set to Brute force, the scene has a large amount of lights (e.g. as in an interior scene) you could set the Primary GI engine to Irradiance map [4].
  • If the Primary GI engine is set to Irradiance map and you are using Vray Lights check “Store with irradiance map” in the VRayLight Modify panel [7].

Configuring VRayPhysicalCamera

  1. After inserting a VRayPhysicalCamera into the scene, in the modify tab set Film Gate (mm) to 45 [8].
  2. Set Focal Length (mm) to 35.
  3. Set F-Number to 8.0 [8].
  4. Check Exposure.
  5. Check Vignetting and set to 0.75.
  6. For White Balance select custom and set the color to 148,51,255.
  7. Set Shutter Speed (s^-1) to 300.
  8. Set Film Speed (ISO) to 200.

Configuring VRaySun and VRaySky
VRaySun

  1. After inserting a VRaySun into the scene, accept if asked, “Would you like to automatically add a VRaySky environment map?”
  2. In the modify tab for the VRaySun check enabled.
  3. Check invisible.
  4. Set Turbidity to 2.0.
  5. Set Ozone to 0.5.
  6. Set Intensity Multiplier to 1.5 [8].
  7. Set Size Multiplier to 1.5.
  8. Set Shadow Subdivs to 12.
  9. Set Shadow Bias to 6⁄32“.
  10. Set Photon Emit Radius to 4’2″.
  11. Set Sky Model to “Preetham et al.”

VRaySky

  1. If a VRaySky environment map doesn’t exist in the scene, you can add one by going to Rendering > Environment and set Environment Map to “VRaySky.”
  2. In Rendering > Environment > Environment Map, select the Environment Map and drag it to a slot in the Material Editor (Copy Method Instance).
  3. In the Material Editor for the VRaySky check Manual Sun Node.
  4. For the Sun Node, select the VRaySun in the scene to link the VRaySun and VRaySky.
  5. In the Material Editor for the VRaySky set Sun Turbidity to 2.0.
  6. Set Sun Ozone to 0.5.
  7. Set Sun Intensity Multiplier to 1.25 [8].
  8. Set Sun Size Multiplier to 1.5.
  9. Check sun invisible.
  10. Set Sky Model to “Preetham et al.”

Configuring Desired Scene Lighting, Brightness and Environment

  • Adjust the Absolute:World Z-Coordinate of the VRaySun [9].
  • Adjust the VRaySun and VRaySky Intensity Multipliers [9].
  • Adjust the VRayPhysicalCamera F-Number [10].

Notes:

  1. You can also set this value to 1.0 and adjust the gamma of bitmap files manually in the material editor.
  2. This setting is made because we are going to use V-Ray’s Frame Buffer as an alternative.
  3. This item must be disabled as it can conflict with VRaySun/Sky for GI Environment.
  4. Although Brute force will produce more accurate results, it does come at a cost of somewhat increased render times when compared to Irradiance map (approx. 1.2 x Irradiance map time at Medium preset and ceteris paribus) .
  5. The system default is .01 but can be adjusted for controlling render quality vs speed. Lower values reduce noise but increase render times. The suggested values are 0.005 (Very High), 0.01 (High), 0.02 (Medium), 0.04 (Low) and 0.08 (Very Low).
  6. Typically you will also need to adjust the Noise threshold as the default may produce too much noise. A good value is, for example, 0.005. You can also controll the noise directly from the Image sampler rollout, if you uncheck the Use DMC sample thresh. parameter, and adjust the Clr. thresh instead (e.g. to 0.005).
  7. This setting will increase irradiance map generation times but reduce render times.
  8. These settings are recommended and may vary with scenes and user preference.
  9. Get more information.
  10. Get more information.

Additional Information:

  • Leave all subdivs anywhere at their default values. They won’t have any effect anyway – the 100 AA subdivs will almost certainly override everything else.
  • Avoid using sharpening AA filters. They can make the noise more apparent.