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In this movie we're going to have a look at something called ambient occlusion. We're doing Chapter11_10.c4d, and if you want to follow along, you can open up that project too. Now if you've never used 3D applications before, you might think. What is ambient occlusion. Well I will tell you. Now in order to see ambient occlusion at its best and worst, we need light to accentuate our scene. Now, before we add a light what I'm going to do is just hit shift R to render my scene to the picture viewer.
So that I can compare it once I've added the light. I'll close the picture viewer and then we're going to add a light that we haven't used before, a target light. Now target lights are great. You can move the light around and it always points towards a target. And here's my target and if I move the target around. You'll notice the light follows. Now, I can change the target for the light. I could select the light and go into the Target tab of the light and drag any element into the Target Object dialog or menu and you'll notice that now becomes the target.
And this is great. If you got something that's moving around and you want the light to follow it, this is all you need to do. And the light will follow it wherever it goes. So we've now got the light targeted onto the robot. So, once I've got my light in there, what I want to do is render it and see how it looks. So I'm going to hit Shift-R again, to render to the picture viewer. And now we can compare. Before and after. So I can go in here and select without the light, with the light, and just see how it looks and decide which I like.
Now, I like it with the light but you'll notice that when I've added the light, notice particularly at the bottom of the robot feet, we start to lose a bit of definition and detail. And this tends to happen with 3D softare. It's very difficult to render shadows in areas where there isn't a lot of distance between the surfaces. And you'll notice particularly in areas like where the feet touch the floor here, we start to lose definition. Now, you can accentuate that by adding global illumination.
And complex area lengths, but that will increase render time. So instead what we're going to do is use something called ambient seclusion which is an effect. Now ambient seclusion can be applied in one of two ways. It can be applied as a shader to the individual object via materials. Or you can add it to the complete scene that's in effect and that's what we're going to do here. And basically what it does is it calculates the distance between objects and it creates a realistic shadow or colloration just to accentuate what should be a shadowed area in the image.
And it's really fantastic. So, what we're going to do is we're going to add it to the complete scene. And to do that, we do that in the render setting. So we go to render. Edit render settings and you click on effect here and choose ambient clusion. Now that's the default settings so lets render it. So lets hit shift r to see how it looks with ambient clusion added. Now you may notice it may increase render time slightly. Now you may find it increases render time a little bit, but please trust me, it won't be as much as if you had used global illumination, and complex area lights.
But you'll see that we have made quite a difference. Notice the shadow in the areas, like tight areas between the head and the body, the feet and the floor Is much better. It's looking much more realistic. Now we can go into our settings and make adjustments to them. So let's close the picture viewer and have a look at what we can do. One thing that can really help without really losing too much is reduce the maximum ray length. And if I reduce that to 50 and hit shift r again. You'll notice it should be a bit faster.
Okay, six seconds we've got now and we can compare before and after and we see we our losing a little bit of detail. But if I compare it to with and without, were still getting an improvement. Now one thing you can do is you can output your ambient occlusion as a seperate pass and then boost it in After Effects by using levels or something. And that's something that I do often. Or you can add contrast to it, so I could put contrast up to 50%, hit shift r, and see if that a, adds or removes any time. B, makes it look better.
So again we're looking for a tradeoff. So this time if I compare that to this one, you'll see we're getting a slighter better result and there's not that much differnece between that one and that one, although there is a bit. So, it is a tradeoff, you have to kind of keep playing with these settings. Maybe we need. 75 centimetres for our ray length. Maybe we can decrease the accuracy down to 20%. We can also take the samples down. So take them down to two and 16 and lets have a look at how that looks.
Okay, it is getting faster. It feels faster. Down to five seconds. And again we're still getting the improvement in those shadow areas. So you can play around with these settings. Maybe the contrast is a little too high now so I might need to. Bring that contrast down to about 20%. So, you want to play around with these settings until you get the right trade off between image quality and file size. And as I said, have a think about rendering out your ambient to occlusion pass.
Now, you'll see what at four seconds. So, four seconds with ambient occlusion. And it's still much better than it was without the ambient occlusion. Now, remember we can now put that as a separate pass. So, we could if we go to our multi pass options, we could click on multi pass. And I could add ambient occlusion as a separate pass. And now when I hit Shift+R to render I can have a look at my ambient occlusion pass and I can see that well I could take into After Effects.
And I may be blur it and enhance levels of it and that might give me a little bit more shadow. So you'll see by comparing the image and the passes and looking at the history and comparing frames, you can start to come up with a compromise between image quality and render times. And apply ambient seclusion to really improve the image quality quite considerably for quite a small trade off.
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