Join Brian Bradley for an in-depth discussion in this video Using the Spot and Projector light types, part of SketchUp: Rendering with Twilight.
As we have already noted, for many artificial lighting situations a very useful light type to have available is Twilight's Spot light. As with our Point light, we have a Spot light layer set up in the scene. So let's come up to our Window menu, come down to the Layers option, and you can see in our Layers dialog we have our Spotlight layer (Light_Spot). Before we work with our Spot light, however, we'd just like to take a moment to explain what this Light_ Placement_Guide layer is all about. In fact, if we put a check in the box, you can see this reveals a simple line in our scene.
This has been placed here as a Light Placement Guide. To demonstrate how we would use this, I'm just going to come up to the Twilight toolbar and click on the Add New Spotlight icon. To create a new Spot light in the scene, we essentially need to use three mouse clicks. If we just demonstrate, the first click will actually set the creation point in the scene. Now, as we move our mouse around, in typical SketchUp fashion, you can see we snap to certain pieces of geometry in the scene. As our guide object is set up exactly where I want my Spot light to be in the scene, I'm just going to snap to the End point of my line and then left-mouse-click.
Now we have set the creation point; our second click will create the light object itself. Now, if I move the mouse, you can see we have this rubber band. Essentially this means we can now orient or point to Spot light in our scene. As I want to point straight down on our sample spheres, I'm just going to again snap to the End point of our placement guide and then left-mouse-click once more to create our Spot light for me in the scene. Now, of course we can create a Twilight Spot light without any placement guide; it is not a requirement. But hopefully you can see how handy it can be just to have such an object set up in the scene.
And of course we already have a Spot light in the scene, so we don't need our newly created one. We could just go and delete it. But as you may have noticed in our Layers dialog, we have a new light layer (TWL_Light_Layer) that is being created. If I just delete the light object, that will remain behind. So I'm just going to use Alt+Backspace and that actually gets rid of both of them. Now, of course we can hide our Placement_Guide layer and unhide our Spotlight layer (Light_Spot). As we have once again added a new light object into the scene, we're going to want to render it in isolation. We want to see what kind of illumination it adds to our environment, and of course what kind of emission pattern we get from it.
So let's click on the Open Render dialog icon, and let's click to start a new test render. We now of course get a completely different emission pattern as compared to our Point lLight. We don't have omnidirectional light in the scene. Now we have got a very, very focused spot of light. Interestingly, as well as the expected spot shining down on the floor, because we have intersected our light emission with this upright shelving unit, we actually get a very nice visual representation of the cone of our light emission also. Now, of course we're going to want to work with our light object's control parameters, so let's dismiss our dialog, select our light object in the scene, and in this instance I'm just going to right-click, come down to the Twilight entry, and click on the Edit Light flyout.
As with our Spot light, we're taken straight into the Standard tab of our Light Editor. This is because these controls are as relevant for our Spot light as they were with our point light. In fact, as I want soft shadows to come for my Spot light, let's alter our Light Bulb Size. Let's set a value of 15 in here, and as you can see, our light object updates in the scene. Because we are working with a Spot light, we are going to be interested in the Spot-light-specific control, so let's come to the Spot tab and you can see we have a Falloff and a HotSpot option.
These of course are the controlling parameters for the cone of light that we get from our Spot light. If we just come back into the Render dialog, you can seem essentially those two controls are creating this particular effect for us. We can of course change our light emission a little bit. Let's come back into our Spot controls. Let's set some values in our Falloff and HotSpot settings. In fact, let's just change our Falloff to 90, but we will keep the HotSpot at the default 40, as it was in our existing test render. So let's come and let's take another render.
What we get now of course is a very different termination of light from our cone. Whereas before we had a harsh cu off at the edge of our Spot light's cone, now we see this gradual falloff into darkness. We do still of course have our original hotspot, the bright spot at the center of our light cone. We even have soft-edge shadows inside of that because we increased our light bulb size. Now, you may think that the controls in our Spot tab and the ones found in our Standard tab really are all we have in terms of controlling what we get from our Spot light object.
But that in fact would not be the case. Twilight has a very cool piece of functionality whereby it allows us to essentially convert one light object into another light type. If we just come up to the Convert option found at the top of our Light Editor, you can see we can actually convert our Spot light into a Point or Projector light. As we have examined the Point Light already, let's click on the Projector option. And you can see, that changes the look of our Spot light object in the scene. Again, the Standard controls are all relevant when it comes to working with the Projector Light, so we need to keep in mind that these options are still very much usable, but of course we're going to be interested in what's found in our Projector tab.
So if we just select that, you can see essentially we have two options: we can control the size of our Projector Light and we can load a Texture that can be projected into the scene. Now, I'm just going to set my size to a value of something like 512, which as you can see, because the Width and Height are locked, updates automatically. Now, we can see that our light object in the scene has become quite large. That would be absolutely fine if that is what we wanted. It's not quite how I want to work things at this moment in time, however. We do need to bear in mind that our Width and Height options here will work in conjunction with our Light Bulb Size inside of the Standard controls.
So if I set this down to a value of 2, you can see that completely changes the size of our Projector Light object. We haven't of course loaded a texture as of yet, so let's come back into that tab and click on the Texture button. Now, if we have set things up according to our introductory videos inside of SketchUp, we would automatically be taken into our Exercise_Files folder. We can just navigate then into the Texture_Files folder. And I'm going to choose this Water_Displacement image. To see how that looks projected into the scene, we will of course need to take a render.
What we get of course is a very interesting effect. We're only getting grayscale values from our projected image at this moment in time, because it is a grayscale image. If we had chosen a color image, we would be projecting the color into the scene also. As I'm sure you can imagine, there are quite a number of specialized scenarios where this Projector light could come in very handy. So we have seen that our Twilight Spot light adds quite a bit of flexibility to our artificial lighting toolset. We can use it as a spotlight. We can use it as a Projector light.
But that isn't all that our Spot light can do. In our next video, we will take a look at how we can add an extra level of realism to our artificial lighting setups by means of IES profiles.
- Installing Twilight
- Adding the Physical Sun and Sky
- Employing Point, Spot, and Projector light types
- Using light emitting materials
- Managing the Quality Presets
- Positioning your scene view
- Working with the camera's Focal Length setting
- Creating diffuse, reflective, and refractive surfaces
- Rendering out an alpha mask
- Setting up a depth render