Beginning Lighting and Rendering with 3ds Max and V-Ray

Fine-tuning Global Illumination, Image Filter, and Color Mapping

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This segment focuses on fine-tuning the global illumination, image filter and the color mapping parameters for draft renders.


  • Global illumination
  • Image filter
  • Color mapping

About this video

Jamie Cardoso
First online
21 December 2018
Online ISBN
Copyright information
© Jamie Cardoso 2019

Video Transcript

[Audio starts]

In this segment, we’ll focus on fine-tuning the global illumination, image filter and the color mapping parameters for draft renders. The first step is to adjust the global illumination key parameters for draft renders; choose the appropriate image filter; and fine-tune the best color mapping parameters. Next, let’s open the GI tab. By default, the primary engine is set to brute force. But for the purpose of this quick exercise, we’re going to use the irradiance map. Again begin to enable the export mode. Expand the irradiance map parameters. By default, the current preset is set to high. Because you’ll be doing some test renders, we’ll set the preset to low. We’re going to enable the show direct light. This is very useful, especially when you’re working with sunlight. During the pre-calculation of the irradiance map, if you don’t have that enabled, you won’t be able to see exactly where the direct light is affecting the scene. You’ll only see once you saw its rendering. So this will enable you to see and stop if necessary the pre-calculation before it jumps into the renders, so you don’t have to waste time waiting to render starts to realize that the direct light is not affecting the areas they’re supposed to. So it’s always good to enable that. This function here is to show calculation phase. They share the irradiance calculation phase before it starts rendering. Expand the light cache rollout parameters. The value of 1000 should be okay for a test render. Just to make things a big faster, you can reduce that to 700 just as a starting point. Let’s go back to the V-Ray tab again. Under the image filter rollout parameters, by default is set to V-Ray VRayLanczosFilter. For the purpose of this exercise, we’re going to change it to area type. However, feel free to pick another image filter type from the list. Let’s expand the color mapping rollout parameters. By default, the color mapping type is set to Reinhard. Let’s change it to exponential type instead. Exponential color mapping is extremely useful to help correct areas of the render that are overly bright. Also it makes your raw renders more realistic. Enable the sub pixel mapping function. This function is quite useful to help remove white-dotted artifacts in render. By default, the color mapping only, is enabled. This is quite useful because the gamma is already enabled so we don’t need that. If the gamma was not enabled, you could actually use color mapping in gamma. So you’d actually use a gamma in a frame buffer to render without having to enable the gamma setting here. Obviously, some of you might not have the latest version of V-Ray 3.6 or V-Ray Next. So for those that don’t have it, you always need to enable the gamma in the scene preferences dialog. This obviously needs to be color mapping only. Otherwise, you’ll be doing it twice. This segment is not concluded. Global illumination, image filter and color parameters play a crucial role in speeding up the test renders and balancing the exposure controls.

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