Rollover image for wireframe
This tutorial is a breakdown of the workflow required to convert an interior scene that has been setup for another renderer for rendering with Arnold. Scene setup and rendering should take no longer than an hour. The scene used in this example is part of this collection of architectural interiors.
The workflow covers the following topics:
Another tutorial that demonstrates different ways to approach lighting a room can be found here.
- The scene is lit very simply with Quad lights positioned outside of the windows of the room. The Color Temperature has been set to that of daylight (5500). Leave the default light Samples setting at 1. For final rendering, increase this value to 4 to reduce any noise in the shadows.
- Increase the Exposure of the light to around 20.
- Use a Directional light to simulate sunlight coming through the far window. Increase the Angle slightly to around 0.2. This will give the sunlight a softer edge to the shadow on the floor. You may need to increase the Directional light's Samples if you do (3 should suffice). Enable Color Temperature and choose a slightly warmer temperature like 5000.
Scene lit with Quad lights outside of the windows and a Directional light representing sunlight
To preview how the lighting will affect the scene, you can apply a Standard Surface (reduce Specular Weight to 0) shader override to the scene. This effectively creates a 'chalk preview' of your render and allows you to focus purely on lighting without being concerned about shading.
Reducing the Diffuse samples to 0 will effectively disable indirect lighting. This is useful when you want to test render direct lighting in the scene and will also be quicker to render.
Diffuse Samples: 0 (disables indirect lighting)
- Connect the diffuse color map to the Base Color of an Standard Surface shader.
- Connect the bump map to the Bump attribute. Reduce the Bump Depth to a small amount like 0.03.
- Increase the Specular Weight to 0.3 and increase the Specular Roughness to 0.2 to give the floor a glossy appearance.
Information about Specular Fresnel can be found here.
- Assign a Standard Surface shader to the mirror and rename it 'Mirror'.
- Reduce the Base Weight to 0.
- Increase the Reflection to 1.
Here, we will use Thin Wall and SSS to provide the effect of translucency with the curtain being lit from behind.
- Assign a Standard Surface shader to the curtain and rename it 'curtain'.
- Enable Thin Wall under Transmission.
- Increase the Sub-surface Scattering to around 0.5.
Rollover image to see the effect of translucency on the curtain
Any glass surfaces will need to have Opaque disabled, otherwise any shadows cast by the object will always be solid and not pick up the Transmission color or density of the shader.
Ensure that the polygon face normals are all facing in the right direction (especially important when rendering glass surfaces with Arnold).
- Select the window geometry and disable Opaque.
- Assign a Standard Surface to the glass door and rename it 'Glass'.
- Reduce the Base Weight to 0.
- Increase the Specular Weight to 1.
- Increase Transmission Weight to 1 (this makes the glass transparent).
- Increase the Index of Refraction (IOR) to 1.5 (glass).
- You can also add a tint to the glass very easily by adding a subtle hue to the Transmission Color.
- For the final render, the Camera (AA) settings were increased to 6.
- The Diffuse Samples were also increased to 6 to reduce noise in indirectly lit areas of the room. The images below show the difference between rendering 2 (default) Diffuse samples and 6.
Rollover image to see difference between 2 and 6 Diffuse Samples
Care should be taken when increasing this value as your render times will increase dramatically.
More information and tutorials about removing noise can be found here.
Diffuse Ray Depth
The images below were rendered using a Diffuse Ray Depth of 1 (default) and 4 (rollover image). You can notice a clear difference in the amount of bounced light around the curtain for example.
Rollover image to see difference between Diffuse Ray Depth 1 (default) and 4
Note that render times will linearly increase with regards to the number of ray diffuse bounces and therefore care should be taken when increasing this value.
Transmission Ray Depth
You can 'clearly' see the difference in the glass vases when increasing the Transmission Ray Depth in the images below.
? 2 4 8?
More information about rendering glass surfaces can be found here.
That concludes this tutorial on converting an interior scene for rendering with Arnold.