Learn how to direct the intensity and softness of a spot light.
- [Instructor] For the key light in this triangle setup we'll use an Arnold spotlight. It's going to represent direct sunlight coming through a window. There are other options for daylight such as the Arnold distant light type which is very similar to a 3DS max directional light but in this case we're using a spotlight because it's easier to art direct. Specifically with a spotlight we can control the light coverage without altering our set and we can add a global modifier to crop the spotlight.
Let's create the spotlight, go to the create panel, lights, from the pull down list choose Arnold, click the Arnold light button, in the top view click and drag to create the light and it's target, release the mouse, and then right-click to exit the tool. With the light still selected go to the modifier panel and rename it. Let's call it key light. I'll want to rotate the light without using it's target, so let's disable the targeted option and set the target distance to 20 feet, type in 20 and press enter.
So that we can always see the cone of the spotlight in the view ports, let's go to shape rendering and enable always visible in view port. I've got a helper object to precisely align the light and that helper object is hidden, so let's go ahead and un-hide it. Open up the layer explorer and turn on the visibility for the lights layer and we can open that up and we can see it's got a spot point helper in that layer and here it is in the view port, that green cross.
While we're here, let's move these other lights into the lights layer. Select one of them, hold down control, select the other, and then click and drag those on top of the lights layer, release the mouse and they've been added to the lights layer. Let's make sure we de-select, just click in the view port and select nothing. Close the layer explorer. Now we're ready to align the spotlight to the helper. Select the spotlight only and then on the main tool bar click the align button and then click on the helper object in the top view port.
The align selection dialogue comes up. We want to align the position in X, Y, and Z and we want to align the rotations as well, down here, align orientation in X, Y, and Z. Click okay and now we've snap aligned that spotlight to the existing helper. Let's do an active shade rendering of the physical camera. Click on active shade. Here's our first rendering of that light in position, now let's change it's parameters with it still selected in the modify panel and down at the bottom we have the exposure.
Let's go ahead and set that to a value of 11 and now we have a very bright shot. Next, we can change the color temperature and that's found in color slash intensity. Select the Kelvin option and we'll set it to 6,000 degrees and that makes it a bit warmer. We're seeing a default quad light so let's go ahead and change the type. Under shape, emit light from, type, switch that over to spot and now it got a spotlight.
Let's bring the cone angle down. So that's here, cone angle, set that to 20 degrees. So I can click and drag that down, I can just type in 20 degrees. Now we've got a very soft spotlight there. We want it to be a little bit harder edge and that's controlled with the penumbra angle and that's the angular value that is shown here as the transition between the fully illuminated center of the light and the outer edge here which is fading off to zero.
So the main cone angle is 20 degrees and the penumbra angle is now five degrees so the hot spot is 15 degrees in the center. Let's set the penumbra angle to only one degree and press enter and now we've got a sharper spotlight and because I want this to look like it's coming through a square window, I can turn the roundness factor down to zero. So just click and drag on that roundness, bring it down to zero, and now we've got a square patch of light. The last parameter we want to look at is the softness of shadows.
Let's get in closer in the active shade window. So click on that window and then use the mouse wheel to zoom in on the shadows and then we can change the radius of the light here. So let's set it to zero just to see what that looks like. Type in a zero and press enter and now we've got very sharp shadows there. A good value for this would be about three inches to match the softness of the penumbra angle. So let's set this to three inches, three and then a double quote, and press enter and once that finishes rendering we can see we've got softer shadows there.
Alright, we can zoom back out in the active shade, just click in it and use the mouse wheel to zoom back out to a one to one pixel size. That's how to add an Arnold spotlight and change up it's basic parameters.
- 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