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Let's go over the Vector nodes that are in Blender and show you how to do some vector math. I know you all slept through your vector calculus classes in college, or managed to escape out to have taken them, and so now it's going to come back to haunt you. But I'll show you how easy it is to do in Blender. First of all, go ahead and click the Render button here to go ahead and give us a great render of Suzanne. So what we can do now is use this Map Value node to alter this image. Map Value is a general-purpose math node.
Actually, you can do vector calculus and all sorts of neat stuff inside of it, but what it does is a complete transformation of some input values to some output values, subject to some clipping. So let's walk through it here. What the map value is doing is it has an Offset and a Size, a Min and a Max. The offset takes the number that comes in, in this case the Z value, remember Z is distance from camera, takes that number and subtracts 5. That's what the offset does.
Anything that comes in first off takes off 5 off the top. Next, it multiplies the result by size. So in this case, it cuts it into half. Then if these are enabled, which they are, it subjects that result to a minimum and maximum. So if the result of subtracting 5 and dividing by 2 is less than 0, it puts out a 0 as the value for that pixel. If it's greater than 1, it will put out 1.
You can disable this and then it will put out whatever the value is as a result of that little calculation. That's all it does. So what we've done is I've fed this to a Color Ramp node. Color ramps are also in materials, and like pretty much all over in textures and everything. A color ramp is a general way of mapping a number to a color. So 0 is on the far left and 1 is on the far right. So in this case we have two colors, and if we click over here, we can select the left-hand bar, and if you just click-and-drag, you can grab that bar and slide it anywhere.
Wherever that bar is, you get the color that's indicated by that swatch. If there are no colors to the left of the bar, then you get just a solid red. Any number between, let's say this is about a half, so this is about 20%. Anything between 0 and 0.2 becomes pure red. On the other side, we have the other opposite extreme. You can add colors. Add any number of the colors in the middle that you want. So you can have any kind of a gradient of colors that you want to transform through.
But this color over here then is on the right, and it represents a value of 1. So right now, about everything between 0.8 and 1 will get a solid blue color. What this does is it adds false color to this image based on the distance it is from the camera. We've just created a kind of a sonar ranging mechanism that you've seen in all these NASA photographs and like that. That based on the depth and based on the distance from the camera, we're going to create an image that has false color, and that shows us visually through color, how far away that particular pixel is from the camera.
Moving on to the others, let's go ahead and change scenes now over to Normal Dot clouds, and go ahead and press E to execute the noodle. What we have here is a kind of a neat use of the Texture node along with the Normal Vector nodes. What we've done here is we've taken a Normal cloud texture, which appears here as a cloud of colors, and we've set it two things, one is to the offset, and the other is to the scale. The offset is a vector node, because it's blue.
So we've used the Normal node here to alter the Normal Vector that comes out of this. What is the Normal vector? Well, the easiest way to visualize it is it's a ball of light, and the light is apparently shining down on top of the ball. Now the light is apparently shining right from us directly on to the ball. Now over here it's shining over to the left, and you can see that we are offsetting the texture based on where I place the apparent light source.
I'm just clicking-and-dragging on the ball to make it change colors. The other neat thing you can do then is to scale the texture. Right now you can see it's very stretched in the X direction, as we move this down over to here, we're going to be stretching it in the Y direction. So the location of the brightest part of the globe, sort of indicates how it's being stretched. This would make a great little overlay or texture to add on to the background of a sunset, let's say. So then once you feed that to the Texture node, now you have a colored image that you can use to add color or a texture to any image.
Another thing we can do that's really cool with vectors and normals, you can go ahead and change and select this scene called Normal.Lamp and press E to execute. Here we have an image rendering of Suzanne, and it's taken from the Map Value scene. It's feeding it in to this vector here, the Normal Vector. This Normal node is going to take the input vector, and then change it somehow, based on the location of the bright spot of the ball, and it's going to feed the dot product of the vector, and you can think of the dot product, sort of like the net effect, if you will, to an RGB Curves.
RGB Curves in this case takes the image and simply brightens it. If it was black, it makes it half-gray. From here, you can see that with this Viewer node, what the Normal Vector does it takes the Normal Vector and then alters it, and you can see how it's altering the apparent light's direction from the image. So this is the way we can change the lighting direction of a CG scene in Post Pro without actually having to change the real lighting. Then the Curves node changes and alters the colors, takes the image and based on this factor, alters the brightness or darkness of the image.
So now, as we change the light source, we can make her brighter, and darker, and also then just change the direction from which the light is coming. So that's how you can use the Normal node and the Normal Render Paths through and RGB Curves to change the apparent light direction and light intensity. So, vector math isn't so hard, is it? No, we got it.
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