Rendering with Sunlight

This tutorial explains how to set up sunlight and VRay light to light up a building's interior.

Approach to Render a Scene with VRay

The approach I used to render this scene is: Firstly, use a single SunLight to simulate the outdoor light. In this case, the outdoor sun light is the main light source. Test render the scene and add a VRay light to add additional light and shadow to the scene. The VRay light is used to simulate the light from outside to give small objects some shadow because the Sunlight and Environment lighting will not give shadows to small objects.

Steps to Set Up the VRay Render

Step 1: Go to Create tab -> System -> Sunlight, to create a sunlight system. Then, place the Sunlight outside of the building as the image shows:

Step 2: Set up the Sunlight parameters: Set the shadow type to "VRayShadow", set "Multiplier" to "3.0", "Color" to White.

Step 3: Set up the VRay rendering parameters in Renderer tab by pressing F10.
First, under "V-Ray: Image sampler(Antialiasing)", set "Image Sampler" type to "Fixed", and turn "Antialiasing Filter" on, type to "Catmull-Rom".

Tips for selecting "Image Sampler" types:

1. Use "Fixed" when the rendered scene requires a lot of blurring effects such as Depth-of-Field.

2. Use "Adaptive subdivision" when the rendered scene does not require any blurring effects such as Global Illumination, Reflection and Refraction, Area Light/Shadow, Transparency).

Step 4: Under "V-Ray: Indirect Illumination(GI)", tick the box before "On". It will enable VRay GI. Set "Primary bounces" -> Multiplier to "1.0" and "Secondary bounces" -> Multiplier to "0.5". Set the "Secondary bounces" to "0.5" will prevent the scene being too bright because we will set up the Environment as well for Skylight. If the render result is too dark, you can always increase the "Secondary bounces".

Under "V-Ray: Irradiance Map", "Built-in presets" -> set "Current preset" to "Low". It will reduce the test rendering time dramaticly. Under "Options", tick the box after "Show calc. phase". This option will show you differenct phases while you are rendering, so you can quickly spot problem areas before the render finishs.

Under "Mode", set "Mode" to "Single frame".
Step 5: Under "V-Ray: Environment", turn on "GI Environment (skylight) override", set the color to blue (R=173, G=208, B=255), set "Multiplier" to "4.0". This setting will override MAX's default environment settings. If this option is not turned on, MAX will use the default settings for skylight.

Below shows the differenct phases of the render:

Phase 1:
Phase 2:

Phase 3:

Step 6: As you can see, the render is too dark. And there is some antialiasing problem as well in the edge of the sun light area. We will change some settings to eliminate the problem.

First, go to "V-Ray: Color mapping", set "Dark multiplier" to "2.0", it will give the dark area more light.

Second, go to "V-Ray: Image sampler(Antialiasing)", change "Image sampler" type to "Adaptive subdivision". And go to "V-Ray: Adaptive subdivision image sampler", set "Min. rat" to "-1" and "Max. rat" to "2".

Third, got to "Create" tab and create a "VRay Light". This light will be used to simulate light coming from outside and gives small objects some nice shadows. Check out VRay Light settings with the image below.
Fourth, select Sun Light system and go to "VRayShadows params", tick the box before "Smooth Surface Shadows".
Fifth, change VRay render settings according to the image below. Note, set the "Secondary bounces" Multiplier to "1.0" will increase the brightness of the bounced light.

Final Render Result:

[Download Scene File:]

The scene file includes: .MAX file for 3dsmax 9.
Download Scene File [226KB].

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