In this tutorial we will cover how to convert a scene that has been setup for use with the mental ray renderer to MtoA. We will cover how to use the Gobo filter in combination with a Spot light and Volume Scattering to create a hyperspace effect. We will also look at various ways to adjust the spot light to enhance the lighting in the scene. Finally, we will add a Filter Map to the camera to provide a vignetting effect.
|The Maya scene file can be downloaded here.|
The original Maya scene files for this series of tutorials can be downloaded from Autodesk's Hyperspace Madness production.
- Start off by creating a Spot light. Position and rotate it so that it is pointing towards the camera. Under the Arnold attributes of the spot light, enable Color Temperature and use a cool blue value of around 15000. Increase the Exposure to around 7.
- Open the Render Settings and go to Environment. Create an aiVolumeScattering by selecting the icon to the right of Atmosphere.
- Increase the Density to 1. You maya notice some noise in the volume scattering. This is fine for test rendering but for final scene rendering you may want to increase the Volume Scattering Samples value (in this case a value of 15 was used).
Volume Scattering Density 1
- Go to the Arnold attributes of the Spot light and add an aiGobo filter. Change the Filter Mode to mix and increase the Density to 1.
- Increase the Scale S and T to 0.5 of the Gobo filter. This will scale down the fractal texture that will be used in the Slide Map.
- Connect a fractal texture map to the Slide Map of the Gobo filter.
- Increase the Amplitude value of the fractal texture. This will add more contrast to the fractal which will provide the light beam effect that we want to see in the volume scattering. Increasing the Frequency Ratio will create more finer light beams.
Fractal texture added to Slide Map of Gobo filter
- Next, we will add some variation to the noise beams. Disconnect the fractal map and project a ramp texture to the Slide Map. Connect the fractal texture to one of the colors of the ramp. Change the ramp Type to UV Ramp. Experiment by adding some noise to the ramp.
Final shader network for spot light
Per-Light Attribute Scaling
If we wanted to adjust the specular highlight on the front of the space ship, we could adjust the exposure of the spot light. However, that would also increase the volume scattering effect, which is not what we want. A way around this is to adjust the per-light scaling for Specular in the Arnold attributes of the spot light. You can then adjust the effect the light has on the specularity without the light affecting anything else.
Note that these values should normally be left at 1 to produce physically accurate results.
We can use the camera Filtermap attribute to add a vignette effect to the lens of our camera quite easily.
- Open the Arnold attributes for the camera and connect a ramp to the Filtermap attribute. Change the Type to Circular Ramp and the Interpolation to Exponential Down.
Once you are happy with how the hyperspace effect looks, you could try animating it. In the example below, the Time attribute of the fractal texture has been keyframed. The Rotate Frame attribute of the fractal texture's place2dTexture has also been keyframed.