Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member
Hi! Rob Garrott here and welcome to Design in Motion, the weekly series where we explore important fundamentals in the world of motion graphics. Realism in your renders is a very hot topic in the 3D world these days. And one of the best ways to achieve it is using something called Global Illumination. But that begs a couple of questions. What is global illumination and is it right for my project? Let's take a look. In CINEMA 4D here, I have got a very basic scene of a toy plane sitting on the ground and I've got a very basic light setup. It's a four-point light rig with a fill, a key, and a couple of backlights to catch some of the edges on the plane.
And I want to point out that I am working with Linear Workflow turned off. Here in the Attribute manager I have got the Project Settings visible, and Linear Workflow is unchecked. Linear Workflow changes how the lights and textures behave in CINEMA 4D, in the render engine, and I prefer to turn it off when I am working. If you want to work with any workflow on, there's nothing wrong with that. It's just that your renders won't match mine exactly. So let's do a quick rendering of this, Command+R or Ctrl+R on the keyboard. That's going to give us a render of the plane, and it looks pretty good.
We have got some nice even light on the plane. We have got some reflections happening from the Environment Sphere that's in the scene. Some shadow being cast on the ground. It doesn't look too bad. One of the problems with the render engine in all 3D applications is that light in 3D does not bounce by default. And in the real world, light bounces all around your objects and affects how the colors on the object behave, because the light from another nearby object will bounce off your object and suddenly change the color of it.
That light bounce is incredibly difficult for the computer to calculate and so that light bounce is not present in the render engine on purpose. Global Illumination is a way of simulating that light bounce. And it gives a very different looking render. I am going to a turn off the lights in the scene so I will uncheck all these lights and my scene will get dark. Let's render, Command+R or Control+R just to see what that looks like. So there are no lights that are on in the scene except for the auto light, and what I want to do next is to point out the sphere that I have surrounding my scene.
This sphere has a texture on it and that texture looks like a beach scene on a sunny day. It's actually I think a Marina or something like that, but it's a beautiful scene--has some great blue cast to it from the sky and some earthy tones underneath. This image is now going to be used to light the scene when I turn on Global Illumination. That's what Global Illumination does, is it allows you to light with images. And that can provide a lot of interesting color information in the scene that will be difficult to get with just lights alone. So let's go to the render settings, Command+B or Ctrl+B. So in the render settings we are going to go to the Effects and turn on Global Illumination.
When I add that in, I am going to render again, and you are going to notice the previous render only took less than a second or about a second. And I will hit Command+R or Ctrl+R on the keyboard and let's wait and see how long it takes. The Global Illumination process takes a bit of more time to render. And you will notice that it took 10 seconds from one second. That's 10 times as long as the previous render, without lights or shadows. This render looks significantly different than that previous render.
This one has a lot of subtle color information being cast in the scene by the sky object that I have in here. That's this beach scene, remember? And there is a reflectivity and a life in the image that wasn't present before, and some great soft shadows underneath the object. So there is a lot of benefit to using this Global Illumination from a realism standpoint, because now this looks like it's sitting outside and could be sitting just on the ground somewhere. It has a much better feel to it. There is a very important setting in the render settings for Global Illumination called Diffuse Depth.
And the Diffuse Depth controls how many times that light simulation bounces. By default, it's only 1. Now you want to be careful with this. There is a sort of a point of diminishing returns with the Diffuse Depth, and so we don't want to just crank this value up. It's not a, the more you have the better it is kind of situation. There's always a point of diminishing returns. So let's change it up to a 3 and that ought to be about fine. And you are going to notice that the render will take a lot longer--go a Command+R or Ctrl+R on the keyboard. I'm going to have this rendering effect sped up in post, that way we don't have to wait around so long for it.
So here is our rendered scene, and you notice that it took two seconds longer. Now, that doesn't seem like a lot, but relative to the amount of time the freeze render took, two seconds is percentage-wise quite a bit longer to render. This scene really doesn't look that much different. We've got a little bit of a subtle red cast to the floor and that's because the red light bouncing off the surface of our plane and hitting the floor again. But that's really about all the benefit we have, the diffuse adds more color in those bouncy areas. And sometimes it can look really good and other times it can look not such a big deal.
And this is one of those not such a big deal times and you want to be careful. That extra two seconds can translate into a lot longer render time, if you have a very complicated scene. The next effect I wanted to talk about is something called, Ambient Occlusion. And Ambient Occlusion is a component of Global Illumination but we can also turn it on and add in more Ambient Occlusion using the Ambient Occlusion effect. I am going to go to the render settings, Command+B or Control+B and I will go to the effects and add in Ambient Occlusion. It's right there at the very top, because it's so important. Actually it's just alphabetized, but Ambient Occlusion is really important.
What it is, is the darkening of seams on objects. Any place where two pieces of geometry meet, you are going to see the Ambient Occlusion effect. And what that's going to do in this case of this plane, is give me little dark lines right where the wing, for example, meets the body of the plane, and the where the tail parts meet the body of the plane. This doesn't seem like such a big deal until you see a before and after without that on, and I will just render this with it on. Let's hit Command+R or Ctrl+R on the keyboard, and what you are going to see when it gets to rendering, is that we've got now this Ambient Occlusion effect happening in all the joints on the plane.
And it's the most prevalent right where the wing meets the body and this seems like a subtle thing, but it has a lot of realism to your object. In the real world, the Ambient Occlusion effect is everywhere. Any place two objects come together and meet, there is going to be a seam created, and light travels into that seam, but not all of it can back out, so that seam tends to be darker, and that's what the Ambient Occlusion effect simulates. So you can see our plane looks quite a bit better. It's a great looking render. Global Illumination isn't always that important.
And I am going to show you a scene now with a very similar setup but using type where it's not that big a deal. And so let's go in to the Window menu and I'll go to the STANDARD-TYPE. And so this is a Standard Type object that I have set up. It's just an Extrude NURB with a text object underneath it. I have also got the very same lighting rig that I was using on the plane. For my Environment Sphere, I have this reflective scene setup right here which is, once again, that same beach scene that we had before. So all the elements in the scene are essentially the same, except we have type now instead of a plane.
When I render, Command+R or Ctrl+R, I'm going to see a pretty quick render. And the type looks not too bad. I've got a little bit of light coming from the back sides of the type object and the faces are well illuminated. We got a great shadow being cast in the back. And the render time didn't take long at all, about three seconds, so that's a very quick render. Let's take a look at a render settings on this, Command+B or Ctrl+B, and you can see that all the render settings are a default. Let's close that out for just a moment and then we are going to come back and turn on Global Illumination. Now this time what I am going to do is I am going to leave the lights on so you can see what the lights look like.
And that will give us a better idea of what the Global Illumination effect is doing. It's using the Environment Sphere, to light the scene, but it can also use the Environment Sphere and regular lights. So what we want to do is turn on Global Illumination. So let's go Command+B or Ctrl+B to the render settings and go to the Effects pulldown, and do Ambient Occlusion, and then also we are going to do Global Illumination. And those are the two effects that are related to one another, and I want to turn those guys on, and now let's do another render. So you see, last one took three seconds, and I will go Command+R or Ctrl+R and let's see how long this takes to render.
I am going to have this rendering sped up in post, so we don't have to wait quite so long for it. So now we can see the rendering, and it actually it looks pretty darn good. But you have to ask yourself the question, was it worth the 18 seconds it took from the three seconds we had before? The first rendering took three seconds, this rendering took 18 seconds, and it looks pretty good, but it doesn't look that much different. That's always the bounce when you are creating in 3D, is with the effect that I have turned on worth the time it took to render? In this case I would say probably not. We can simulate this same kind of effect without having to use Global Illumination, just by adding a little bit of color to our floor object and cranking up the intensity of the lights.
I will render this scene with both the Environment Sphere and the lights, both contributing to the brightness of the scene. That's why it looks so bright and illuminated. Now I think it looks okay, but personally I don't think it was worth the extra 15 seconds that it took to render this simple scene. Global Illumination or G.I. for short, can be beautiful, but it can also have a huge negative impact on your render times. You should never commit to using it, without first doing a bit of testing and research. For more on working with CINEMA 4D, check out the CINEMA 4D section on lynda.com.
That's it for this edition of Design in Motion. Keep it moving, and I will see you next time.
Get unlimited access to all courses for just $25/month.Become a member
110 Video lessons · 50355 Viewers
86 Video lessons · 13404 Viewers
79 Video lessons · 14814 Viewers
350 Video lessons · 101055 Viewers
Access exercise files from a button right under the course name.
Search within course videos and transcripts, and jump right to the results.
Remove icons showing you already watched videos if you want to start over.
Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.
Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.
Your file was successfully uploaded.