CG Rendering With V-Ray

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When it comes to 3D CG graphics, you really only have two options if you want to get more realistic renderings:

  1. Mental Ray
  2. V-Ray

What sets these engines apart is that they utilize Global Illumination.
When I started my journey away from the default Scanline Rendering Engine I used the Mental Ray Engine because it was recommended by a colleague and because it was already included with 3D Studio Max and thus seemed to be a good economic choice for my company to start out with.
Although I did get great quality improvements when using Mental Ray for my renderings, it did not come without the costs of setup, control, memory and instability. Because of these cons I was led to my other option which was to convince my company to invest some money in Chaos Group’s V-Ray Rendering Engine and so far it has been well worth the money from an efficiency standpoint.

Even though I did get away from Mental Ray I did find that my learning Mental Ray was not in vain as Mental Ray and V-Ray both have similar work flows because they both use Global Illumination. V-ray is just much easier to utilize and is much more stable.
If users are interested in using V-Ray, let me save you the time it took me to do my research and offer up my work flow:
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 [1]
  3. In Bitmap Files set Input Gamma to 2.2 [1] [2] 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 [3].
  2. Assign V-Ray as the current rendering engine (with the default V-Ray settings).
  3. In V-Ray (Tab) > Global Switches (Rollout) uncheck Default Lights
  4. In Frame Buffer (Rollout) check Enable built-in Frame Buffer.
  5. In Image sampler (Antialiasing) (Rollout), switch the image sampler Type to Adaptive DMC.
  6. In Environment (Rollout) check GI Environment (skylight) override.
  7. In Color Mapping (Rollout), switch the Color Mapping Type to Reinhard, Burn Value to .8 and Gamma to 2.2 [1]. Make sure that the Clamp output and Sub-pixel mapping options are unchecked.
  8. In Adaptive DMC image sampler (Rollout) Leave the Min. subdivs at 1and set the Max. subdivs to 100 (one hundred).
  9. In Indirect illumination > Indirect illumination (GI) (Rollout) Turn GI on, set the Primary GI engine to Brute force (As an alternative, you could set the Primary GI engine to Irradiance map [4].) and set the Secondary GI engine to Light cache. Set both multipliers to .8.
  10. 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).
  11. In Light cache (Rollout) set the light cache Interp. samples to 5 and check Show calc. phase (optional).
  12. 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.
  • Optionally turn on the “Use light cache for glossy rays” option to speed up glossy reflections.
  • 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 (i.e. as in an interior scene) and the output is not an animation 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].

Notes:

  1. This setting may vary depending on your monitor configurations. http://www.aversis.be/tutorials/vray/essential_gamma_01.htm
  2. You can also set this value to 1.0 and adjust the gamma of bitmap files manually in the material editor.
  3. This setting is made because we are going to use V-Ray’s Frame Buffer as an alternative.
  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) . Brute force is also recommended for animations. “The IR map has many problems with moving objects, since it is an approximate method, so each frame will have a slightly varying lighting solution. This results in ‘flickering’ of the GI light in your animation.” http://www.aversis.be/tutorials/vray/essential_gi_methods_01.htm
  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).” http://www.spot3d.com/vray/help/150R1/tutorials_unisettings.htm
  7. This setting will increase irradiance map generation times but reduce render times.

Additional Information/Sources:

This work flow is currently a synopses of what works for me and any questions and/or comments are welcome. For some more excellent information, I highly recommend Aversis Vray Tutorials.