Join Rob Garrott for an in-depth discussion in this video Working with Irradiance Cache and Light Mapping for global illumination, part of CINEMA 4D R15 New Features.
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With R15, Maxon has completely rewritten the Irradiance Cache Global Illumination options to provide much faster speeds, combined with a new calculation method that eliminates the time consuming single machine pre-caching of previous versions. I have a very simple scene set up here. It's a room composed of walls that are made up of cloner objects of blocks, and I’ve got a floor and a ceiling, and I’ve got some glowing spheres inside there. Now, in order to actually see what the camera is seeing, we need to bring up a New View Panel. So let’s go to the Window Menu and go to New View Panel.
And I have this View set to be the Render View. If I go the View Options here and I can see I have Users Render View turned on. And under the Camera Menu I am looking through my camera and the scene. So lets take this View Panel and park it over here above the Object Manager. I'm going to grab this grid of dots and drag it to just above the Object Manager. When I get a fat white line above the Object Manager, I'll let go and that will park the window in the interface. Now I can see both what the camera is seeing and the outside world at the same time, and that's very useful. So let's bring up the Render Settings. Cmd or Ctrl+B on the keyboard, and I'm going to adjust the column width here so I can see the names of my Render Settings that I have set up here.
Now I've set up these Render Settings ahead of time so that we can understand quickly what the changes are that I'm making in the file. Now I have a base Render Setting that has the physical render engine turned on, and I've got watermarks set up that tells me the name of the render setting and the render time. And that will render the last step of each of the renders I have got set up, so on all of these I have an individual watermark set up that corresponds to the name of the render setting. So we'll be able to see that. Now under the Physical Render Engine settings, I've set these all to be the default. So it's, the Sampler is adaptive, the Sample Quality is low.
So let's do a render by hitting Shift+R on the keyboard. And this will render very quick, but it doesn't look very good. I have light being cast by the Physical Sky Object in the scene, and it's casting through this grid of windows, and it's making shadows in the scene. But those shadows don't look very good, and I'm getting no light bounce at all. So now let's take this Render Setting up one level and quality by introducing Global Illumination. And we're going to use the Legacy Global Illumination that was present in R14. So let's go back to the Render Settings, Cmd or Ctrl+B, and let's click on Legacy IR.
So I activate that, and you see that Global Illumination popped up over here, let's click on that. And, the first thing you'll notice about the Global Illumination Window is that, it's got a new interface to it. A much more intuitive way of setting your primary and secondary methods than the old pull down that was there before. So now I've got a primary method pull down, and a secondary method pull down. Let's focus on this one. If I click on this, you can see that I have it set to be a Radiance Cache Legacy. Normally the default would be a Radiance Cache. A Radiance Cache Legacy is the old method from R14. Now the Radiance Cache Legacy has been given a little bit of love in R15 to make it a little bit faster than it would have been in the old version.
But it's still going to end up being a lower quality render than we're going to get with the new cache. But let's see what that looks like. So I'll leave that set to be a Radiance Cache Legacy, and I'll hit Shift+R on the keyboard again. The first thing it's going to do is calculate the Radiance Cache Pre-pass, and when it's done it will start rendering the image. Now that rendering only took 12 seconds as you can see here on the watermark. And it looks pretty good, but there's some important details missing from this. The first thing you'll notice is that there's no shadows. There should be some nice crisp shadows that are being rendered on the floor, and on the blocks on the right hand side of the image.
But there's nothing there at all. The old raw image looks okay, but without those details, there's still a lot of information missing. So now let's see what the new Render Setting looks like, the new R15 default. So I'll go back to the Render Settings, Cmd or Ctrl-B, and let's click on this Render setting here, R15 IR default. And when I look at that one, I now have the Primary Method set to be a Radiance Cache. So let's hit Shift-R on the keyboard, and that brings up the Picture Viewer again. So it's going to calculate the Radiance Cache Pre-pass, and then it's going to render the image.
Now you can see that this rendering took longer, 16 seconds. The old render setting took 12 seconds. So what's the benefit? Well as I click between these two images, this is old, this is new. You can see that immediately in the new, the Radiance Cache for R15, I have a much better starting point for my image. You can see that I can actually make out the shadows from the grid lines on the fore, and that’s one of the benefits of this new calculation method. It gives you a much better starting point for your image. So now let’s take this image up one more level in quality. The default calculation method, when you’re using Irradiance Cache, only calculates one level of bouncing.
We need a lot more secondary light bounce in here, in order to get some light into these nooks and crannies in the image, to make the rendering feel a lot better. So let's go back to the Render Settings, Cmd or Ctrl+B. And on the left here I'm going to click on R15 IR light map. Now, the secondary method has now been set to something called Light Mapping, and this is a new idea for R15. And Light Mapping is a new way of calculating the secondary bounces that is much faster and much more efficient. You can see the maximum depth defaults to 16 levels. And normally in the old calculation method, 16 levels would have been very prohibitive to try and render to.
So, let's do a rendering, Shift+R. The first thing it's going to calculate is the Light Mapping Pre-pass. And then once it's done with the Light Mapping pre-pass, it's going to calculate the Irradiance Cache Pre-pass, and then it's going to render the image. So, the first thing you'll notice right off the bat is that our image got brighter. The reason it got brighter is all of that extra secondary bounce. So, you can see down inside these nooks and crannies I have a lot more light being cast in there. The splotches on the walls and the shadows haven't gotten any better, but my image is much brighter, and I can see a lot more information in the dark areas.
Let's go and look at the old render without the light bounce. So there's the image without the light bounce, it looks okay. Here's the image with light bounce, much more interesting because we can see all of that information getting cast down into the nooks and crannies. So now let's take a look at what the shadows can do. Because you can see that we have shadows cast on the floor and sort of on the wall, but they're not very well defined and they don't look all that good. There's also a lot of splotchiness in the image as well. That's being caused by the Render Settings that we have. So let's go back to the Render Settings Window, Cmd or Ctrl+B. And we'll activate the R15 IR light map with crisp shadows, and I'll click on that.
Now, the only thing that I've changed in this Render Setting is something called the Color Refinement under the Irradiance Cache. Now, the way to think of this is the Cache helps you refine the shadows and edges of your image. And we're going to change the samples in just a moment, so the samples will help control the splotches. The Cache Settings will help control the crispness of the image. So the only thing I've changed is the Color Refinement. And the Color Refinement looks at the Contrast Values in the image and focuses on those, and so area of high contrast is going to be where there is a regular piece of the image and that transitions into a shadow.
And so when I do In Render, let's hit Shift+R. And then it's going to go through and do the Light Mapping Pre-pass, again. And then the Irradiance Cast Pre-pass, and then it's going to render. But what you're going to see when this gets done rendering, and you can actually see it here in the Pre-pass already is, we're going to get much more crisply defined shadows. Because that color refinement is looking at those contrast values in the image, and focusing in on those, and concentrating its efforts in those areas. So now as our render finishes here you can see that the shadows have gotten much more defined.
Let's take a look at the old rendering without the Color Refinement turned on. And the shadows are almost nonexistent. We can see the basic outline of where the shadow is supposed to be, but really no information there. When we activate that Color Refinement we get much more defined shadows, and it looks a lot better. Now there's still a little bit of blotchiness in the image, so let's go ahead and activate this last Render Setting and take a look at that. So I hit Cmd or Ctrl+B to bring up the Render Settings again. And now we're going to go to the R15 IR Light Map High, so let's make that the active one. The only thing I've changed now I still have the Color Refinement set to 100, but under the General I've changed the Samples to High.
They were set to be Medium before which is the default value, so now let's render this. I'll hit shift R on the keyboard. And again it's going to calculate the Light Mapping, and then it's going to do the Irradiance Cache, and then it's going to start to render the image. Now, you can see that our Rendered time has gone up dramatically, but this is actually a much faster result than what we'd get under the old settings from R14. Now because of the compression in the movie that you're watching, you may not be able to see the actual subtle changes in the image. I'm going to click back and forth between these two renderings.
You can see that the old one was 54 seconds, this one was at 115. But the place you'll notice the images. So this is the old render, watch this spot right here. When I click on this new one, you can see that I'm now getting a much more defined shadow being cast by the edge of this cube here. Also focus on the foreground right here. You can see that as I go back and forth, this is old, this is new. There's a lot less blotchiness in the color here. And that's what the samples do, they eliminate that blotchiness. Now the last thing I want to talk about regarding the Irradiance Cache is the benefits for animation.
This is a much better system for animating Global Illumination renders. Now let's hit Cmd or Ctrl+B on the keyboard, and bring up the Render Settings, and take a look at this last setting here. And the only thing I did in this setting was I turned on the number of frames that I'm rendering. If you go to the output you can see that I'm going to render from zero to 59 frames. Now I'm not going to render this whole animation. The thing I want to point out is that under the old Irradiance Cache Method from R14, in order for the Render Engine to actually render the animation, it had to calculate the entire Irradiance Cache for the entire animated frames.
So, if you were rendering 300 frames, it would have to calculate all 300 frames before it could even start rendering one. And that was really painful, and it made the Irradiance Cache just about unusable for animation. The new engine does not need to calculate all the frames at once. It calculates each frame individually, and that makes it much more usable for animation. And so now when I hit Shift+R on the keyboard, it's going to start to render the animation right off the bat. You can see that now it's going to calculate this Light Mapping Pre-pass. It's going to calculate the Irradiance Cache. But it's only going to do it for the first frame, and then it's going to do it for each successive frame.
Now because I have the sample set on high for this animation, the first frame is going to take quite a while to render. But when it does render, the thing you're going to notice is that when it goes to render frame two, it will immediately start. And that's a big benefit over the old Pre-pass Method, where it had to calculate it for the entire animation sequence. So rather than watch this whole thing render down, I pre-rendered it here. And you can see the animation where I go from floor to ceiling and resolve on the glowing sphere. I'm really excited about these new Global Illumination options. They make GI faster, easier to understand, and more importantly they make it much more usable for animation.
- Rendering faster with ambient occlusion caching and Embree physical rendering
- Setting up Team Render
- Kerning type
- Creating custom edges with the Bevel tool
- Moving edges and points with the Slide tool
- Using the new sculpting options
- Organizing materials with the Texture Manager
- Creating complex, dynamic camera moves with the Camera Crane Rig