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- View Offline
- Understanding material channels
- Applying materials via projection
- Limiting materials with selection tags
- Texturing type
- Using Falloff to limit the effects of lights
- Working with visible or volumetric light
- Painting on objects and textures with brushes in BodyPaint
- Hiding seams with projection painting
Skill Level Beginner
So far in this chapter we've been talking about the idea that the lights in CINEMA 4D don't behave quite like they do in the real world. And right now we're going to talk about another aspect of light that is not like the real world, but that you can make a little bit more like the real world, and that's something called falloff. In a real light source, light diminishes in intensity as it travels away from that light source, and that effect is called falloff. And you'll hear the word falloff a lot used in 3D applications. Really what it means is a transition, and in this case it's a transition from 100% intensity down to 0% intensity, or from whatever intensity you have set.
The key is that it's always a transition from one state to another. Now when I add a light in C4D--I'm going to add an omni light and I'll click once on the light source. And let's render that. Command+R or Ctrl+R. You can see that our light is doing what lights do, which is pass through objects, and it's illuminating the objects. The reason we're not seeing these objects behind us is because those polygons are facing the other directions. So you can see all these other cubes around us in this grid, but you'll notice that the light is the same intensity. It appears to be diminishing in intensity here, but that's because of the angle of these planes to the light source.
Let's do something different here. Let's raise the light up on its Y axis. I'll hit the E on the keyboard and then drag up. And exact height doesn't matter, but let's hit Command+R or Ctrl+R on the keyboard. Now, you can see that now the light is illuminating all the objects in the scene equally from that point of origin. Now the light appears to be diminishing in intensity in the distance. You can see that we have this sort of dark region out here. But really, what's happening is the angle of light is changing. The omni light radiates light outward from a point source, and as the light becomes more parallel to the surface of the plane--that is the infinite floor-- it no longer strikes the floor, and that gives us the illusion that the light is falling off with intensity.
But these cubes tell us otherwise. You can see that they're the same illumination. The angle is changing and creating different levels of intensity, but the illumination level really is the same. So that begs a question: How do we change it? By adjusting the falloff. Now on your Light source, when you select it, under the Details property is the Falloff option, and the Falloff option is defaulted to None. And so when I click on that, I get some really sort of confusing technical options here. Rather than trying to explain these, because I'm not a light scientist, I'm going to show you a very important thing in CINEMA 4D, which is the Help system.
If I right-click on the word Falloff and go to Show Help, I get an example in the interface. And this is the Help menu inside of C4D. It's an HTML-based system that you can right- click on just about anything in the interface and get a reference for. And for the reference for Falloff, it has a great explanation of Falloff. It also has a visual explanation of the different types. And if I click on this it makes it larger. Let's expand this window out a bit so we can see those light types. Let's bring that over here and scroll down a bit, and let's make the window larger too. There we go.
And we'll scroll to see them. So you can see, these are the different light Falloff types. The default is None. Linear, Inverse Square, Step, and then down here is Inverse Square Limited. Now I prefer to use Linear. It feels the most realistic to me, but there may be times where you need to change these to suit your taste. So let's close up the Help window and turn our Falloff from None to Linear. Now, as soon as we turn it to Linear, you'll notice that we now have this set of rings around our light, and let's hit Command+R or Ctrl+R on the keyboard. And now you can see that our light actually looks a little bit like a spot light.
That's because the light is now being limited. It's diminishing in intensity in a spherical radius around our omni light. Remember, the omni light radiates outward in all directions, which is basically a sphere, and because it's being limited, we see only the places where our objects intersect with that sphere of influence. Now if I hit A on the keyboard, these white rings represent that sphere of influence. So there is a zone from the center of the light out to the outer edge, and this is the falloff region for the light. So it's 100% intensity here, and then it's 0% intensity here.
So if I want to include more of these cubes, I have to take this little orange dot and drag outward until more of my cubes are illuminated. And now if we hit Command+R or Ctrl+R on the keyboard, you could see that our light looks a lot more interesting. It behaves in a much more accurate way. Falloff is probably the most important tool you can use in getting realism in your scene. Turning on Falloff for your light will up the production value every single time. It does require you though, to start thinking about light much more like a lighting designer, and that's always a good thing.