Image Based Lighting with the Dome Light Overview
This tutorial will teach you how to use the dome light feature in V-Ray 1.6 for SketchUp. The VRay Dome Light is a V-Ray specific light source plug-in that can be used to create image base lighting setup.
Step 1. First Render
1.1. Open the scene (which can be found here).
1.2. Open the V-Ray Options menu.
1.3. Go to the Environment rollout and unchecked GI (skylight) and Reflection/refraction (background).
1.4. Doing a test render will produce a black scene at this point.
Step 2. Adding a Dome light
2.1. From the V-Ray toolbar click on the dome light icon and then click anywhere in the scene. This will place the dome light. (screen shot)
Step 3: Adjusting the Dome Light
3.1. The light is too dim with the default settings of the dome light.
3.2. So select the dome light and right click on it.
3.3. Choose V-Ray for SketchUp then Edit light.
3.4. Set the Intensity to 20.0
3.5. Render the scene:
3.6. Reopen the dome light editor and set the Intensity to 15.0
3.7. Click on the Color box. This will open the Color picker Window. Select the light blue color and click Okay.
3.8. Click Okay to close the Light Editor and then Render the scene.
Part II: Attaching an HDRI Image
Step 1. Attaching an HDRI
1.1. Reopen the dome light editor and enable the "Spherical" option. This will wrap the image around a full sphere in the scene.
1.2. Click the checkbox next to "Use Dome Texture" and then click the “m” button.
1.3. Select TexBitmap from the drop down.
1.4. Select any HDRI file from your hard drive.
1.5. Change the UVW Type to UVWGenEnvironment
1.6. Make sure that the "Mapping Type is set to "Spherical" if you are using a spherical HDRI. Notice that we support additional mapping type to match any HDRI type.
1.7. Render the scene.
You will see HDRI file has added trees and clouds to your background and is providing a more natural light to the scene.
Step 2. Adjusting an HDRI
You can adjust the HDRI image rotation both vertically and horizontally so that you can have the correct lighting for your scene and in this case the trees and cloud positions.
2.1. Reopen the dome light editor click the checkbox next to Use Dome Texture
2.2. Click the “M” button.
2.3. Under the UVW section you should see Horizontal and Vertical rotation option. In this tutorial we adjust the "Horizontal" rotation to 155 and the click Okay.
2.4. Increase the Dome light "Intensity" to 45 - The intensity of the HDRI will depend on the HDRI exposure and on the setting of the physical camera that you are using.
2.5. Render the scene.
Notice how we have more contrast and the shadows are very well defined.
Part III: Shadow Quality
Step 1: Better Noise Quality
1.1. Reopen the dome light editor.
1.2. Increase the Subdivs under the V-Ray light editor from 8 to 32. This change will reduce the noise in the scene.
1.5 Render the scene.
Even with medium quality GI settings we are able to produce a very high quality image. As you can see, we have less noise and more defined and sharp shadows.