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Let's go over all of the different ways we can filter an image in Blender and I need to point out that in Shake, almost all of the nodes are called filters. I don't know exactly why, but we call nodes the nodes and then there's different families of nodes. The filter family of node is just a very small subset of the nodes that are in Blender. So I just wanted to go over that. We're going to be learning in this tutorial the nodes that if you press the Spacebar in the Node Editor window, that when you go Add > Filter, then these are the classes of filter nodes that we have.
First up is a general purpose Filter node. It takes an image, the input image, and let's go ahead and press F12 to invoke the renderer so we get a render of the current image of Captain Knowledge in front of some boxes in the background. So the image that we see that comes into the Compositor from CG is very crisp and clear, and looks totally artificial. Lot of the Filter nodes are just designed to soften it up, to make it look like it was taken with a real camera, which is what the audience expects to see.
So the general purpose Filter node has a couple of different filters built into it. First, we can take this very crisp image and just soften it up by a little bit, just kind of blurs around the edges. This filter also can sharpen up and image and make it even sharper and enhance the contrast. This is a very cool effect. It's totally artificial, but it sharpens around and increases the contrast around all the little edges. Again, all of these Filter nodes, you can control the amount of filtering that is done by changing the Factor.
So a Factor of 1 is a full Sharpen, which is a very glaring kind of comic book kind of render, which is kind of cool. Or we can just scale that on down, and I'm just clicking-and-dragging left and right to change this Factor to maybe soften the effect, maybe tighten it up a little bit. We have a couple of other kinds. We have a Sobel filter, which is very cool. This does edge detect and then makes everything neon colored, and just from an artistic standpoint, I really love that effect.
All of these filters, you just take this one filter and then you do other things with it. Like for example, I fed this to a Color Ramp node. So I've taken these Sobel colors and values and then mapped them to this Color Ramp node and now I have almost like automatic rotoscoping or edge detection of the pixels in this image. Again, any kind of input; it can be a CG or a movie or image sequence, whatever you want to do this filter processing on. Another filter family is the Blur node.
I'm going to go ahead and press Shift, middle mouse button, and drag. The Blur filter uses a couple of different algorithms shown here. We have the Mitch, we have the CatRom, Fast Gaussians and Regular Gaussians, Cubics, Tints, Flats, just general purpose kinds of ways in which it blurs the pixels and the surrounding pixels. We can do it in a circular fashion by using Bokeh and Gamma correction on the Gamma-adjusted values of the pixels that are being blurred.
We can do it Relative in percent or to define the radius, or if we turn off Relative there, then we're going to be talking in terms of absolute number of pixels. So what this does is it simply takes each pixel and it blurs it with surrounding pixels. Yet another example of how you can combine these nodes, the size is fed here with the Time node. The Time node goes from whatever value on the left to whatever value on the right, based on the frame range here. So in this case, I've changed the curve to put out a value of 1, so it's going to do a full Blur at Frame 1.
Then as we proceed down through Frame 10, it's going to do no Blur. So the net effect if this was shot out to video would be focusing. The Dilate/Erode node is very cool, in that it takes an image and it computes the pixels around the outside, based on some mask; in this case we're using the actual image itself. We could also use the Alpha values if we wanted to. If the number is positive, it expands the radius.
If it's negative, it shrinks the pixels. So usually one or two is plenty for controlling, for example, matching this up with the Blur, so that only the edges of an object are blurred. If you do a one Dilate, another Erode, and multiply them together or subtract them from one another, then you would come up with an automatic edge detect that you could use then to control the Blur, so if you only want to blur the edges. So lots of cool effects there also based on edge detection and processing.
The Vector Blur node blurs things based on how fast they are moving. In order to grab and use the Vector Blur node, you need to have the Speed render pass enabled in your render layers. We'll just jump over here real quick. In your render layers, you just need to make sure that you've clicked Vector here. Now, the other thing you need to do of course to have a Vector Blur is you need to have stuff moving. So in this case, I have really cranked this box.
Even though it appears still in this frame, I'm applying sort of a Fake Motion Blur, if you will, to this one box, by running the image through this Vector Blur node. The other thing that this node takes into account is the distance of the object from the camera. So even if something is very far away from the camera, but it's moving very fast, it won't get blurred very much. But if it's very close to the camera, z value is very little, then it's going to get blurred a lot.
Here you can see this box is just like really cooking. Captain Knowledge is also in motion as well. So this applies the Blur. You can crank up the number of samples for higher quality Blur, and you can also restrict the minimum amount of speed and the amount of Blur that's applied. So we can crank this down to 1 let's say, and that only applies half the amount of Blur. So you can control the amount of Blur based on the motion of objects in your scene. Next up, we have the Defocus node. Defocus is one of the key components in providing a photorealistic image composite.
By simulating the effect that happens when you have light passing through an iris in a real lens, you get kind of a defocusing effect. That things that are outside the focal plane of the camera become blurred, either in front of the focal plane or in back of the focal plane. Now, in this situation what I've done, and we're going to come over here into the 3D view so I can right click on the camera and show you that the camera has these two fields right over here called Dof Distance and Dof Object. In this case I've entered the name of Captain Knowledge into the Dof Object field, and now the camera will stay focused, if you will, on Captain Knowledge.
When we come in here to the Defocus node, we need the image and the z values, and all we do is we thread the image and the z there and crank the output there. We set our fStop. A lower fStop setting has a wider iris, if you will, and so it has more of an enhanced defocusing on these boxes in the background. We can simply adjust this up to like an fStop of 30, and we can see that the defocusing effectively goes away, because now you have basically a pinhole and you have a very deep depth of field for the camera.
Last up, we have the Glare node. Glare node is very cool. Its one of those commonly requested features that Programmer keyed up and I appreciate that. So we have Glare to add glare to your light saber, to your jet engines, to your light bulbs, anything you want to have some glow to. There's a couple of different modes. We have Ghosts. We have Streaks of light. We have kind of a Fog Glow, like if you're coming out of the fog.
We have a couple of different Quality settings. We can mix that in with the original image; either fully or partially, and now it looks like Captain Knowledge is coming out of the fog. All right. So there are about 20 plus filters in Blender that provide an exceptional array, a very special image processing effects. When used individually, or when used in conjunction with all the other nodes, you can get some pretty astounding results.
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