Learn how to mask a spot light with a pattern.
- [Instructor] To crop the spotlight in certain areas we can apply a Gobo Filter and that works just like a Gobo or Cookie in theatrical or film lighting. Let's do an active shade render of the physical camera and here it is without any Gobo. I want to have a dark bar down the center here similar to the way this window here is constructed. So let's add the Gobo Filter, select the spotlight and in the Modify panel, in the modifier list, choose Arnold Gobo Filter.
And it's been applied but we need to apply a slide map here. So let's do that. We'll click on the None button and then from the list let's do a procedural one a Gradient Ramp. Double click on Gradient Ramp and now we see a ramp applied so it's darker on the left and lighter on the right. Let's edit that. Go into the Material Editor and drag that map over into the Material Editor view.
In the pop up dialog choose Instance and click OK. And then double click on the name of that map to load it's parameters. All we need to do are create a few flags on this gradient. I want it to be completely white then transition to black, be black for awhile then transition back to white. And just to make that easier so that I don't create flags of varying colors, I'm going to temporarily set the interprelation to solid.
This first flag should be white so I'll right click on that and choose Edit Properties and then click on the color swatch. That opens up the color selector. Set the value to it's maximum of 255. Then select the middle flag and set it's value to zero. And we can change it's position while we're here. Set that to a value of 40 and let's just move the flag over a little bit to the left.
Now we need a flag to transition from white to black so click to create a new flag. Just click in the white area and a new flag is created and set it's position to 36 and we'll have a transition from white to black here when we set the interprelation to linear. So we've got full white then transition to full black. That's half of it and we can see the results here.
Alright I'll switch this back to solid and I want to create another black flag so click anywhere in the black area and set it's position to 60. And I need one more white flag so click in the white area and set it's position to 64. Then finally once again set the interprelation back to linear and now I've got what I needed which was full white then transition to black. Stay black for awhile and then transition back to white.
And we've got a nice anti-aliased edge on the bar running through the center of the spotlight. And that's how to apply a Gobo to a spotlight using a modifier.
- Arnold rendering concepts
- Arnold lights such as quad, spot, and distant
- Modifying Arnold object properties
- Filtering light with the gobo filter modifier
- Image-based lighting with Skydome
- Daylight simulation with Physical Sky
- Arnold Standard Surface material parameters
- Diffuse, opacity, and bump mapping
- Rendering refractions with Transmission
- Building an Arnold shading network
- Test rendering with utility map
- Mesh subdivision and displacement at render time
- Atmospheric perspective with scene environment fog
- Rendering a spherical environment with VR Camera