Graphics Reference
In-Depth Information
the number of frames in your animation? Try raising the number of tiles in the Performance panel. The
default is 8 × 8, but try 12 × 12. Under certain circumstances, smaller tiles can give faster results while
increasing memory usage a bit. Most likely, though, the difference in times will be negligible.
In the end, it won't hurt to review the surfacing and lighting in your scene. Ask yourself: Do I really need
that ray-traced shadow, or would a buffered shadow do just as well? Does the subtle blurred reflection on
the table need to be an actual reflection, or can I get away with a phony blend texture mapped to the
reflection coordinates? There's only one way to find out, and you're the judge because it's your image.
This goes the whole way back to Chapter 1 of this topic. The entire exercise of working in 3D is fakery—
what you can get away with. If you maintain that attitude, it will help you make the decisions about what
looks good enough, and what doesn't.
The Compositor
Blender's renderer isn't just for evaluating and drawing geometry. Integrated right into it is something
called a
compositor
. A compositor is like an image processor with an awareness of what's going on in
3D. If you're used to image processors like Photoshop (or GIMP, etc.), you know that in order to, say,
blur the background of a picture, you have to create a mask for it, painstakingly painting around the
foreground elements so the blur effect is applied to the right portion of the image. This is because standard
image processing programs have no idea
what
is in that image. It's just a bunch of colored pixels.
An integrated compositor, though, is much better. Since it's part of Blender's renderer, you can tell it to
blur the background of your render, and it can do it without jumping through a lot of hoops, because it
knows what parts of the image are near to the camera and which are far away. It can tell if something is
moving, to generate motion blur. It can differentiate individual objects from each other. It knows what
light comes from diffuse shaders, specular shaders, ambient occlusion, reflection, and refraction. It even
knows if you've been bad or good.
All of this gives you immense power when completing your renders. That's right: The compositing process
is really a part of rendering. Your images are almost certainly not everything they could be before passing
through the compositor.
Figure 12.9(a)
shows a very simple image that consists of three crinkled orange
balls on a flat plane. It's rather unrealistic.
Figure 12.9(b)
shows that same image after it comes out the
other side of the compositor. It is significantly better. And, while it is far from realistic, it has achieved a
degree of believability that would have been impossible from the raw render.
Getting Familiar with the Compositor
The screen that we're already using to adjust render settings (
Figure 12.1
) has a Compositor window for
its upper half. Blender uses a
node
compositor, which means that the compositing workflow is created by
adding little panels to the screen and connecting them in various ways.
Figure 12.10
shows the composit-
ing workflow (sometimes called a
node tree
or
noodle
) to create a simple glare effect on our sample scene.
Before you begin to duplicate this, you'll have to enable the compositor. If you look at the actual window
type, though, you'll notice that it is called a
Node Editor
. That is because the node interface that we'll be
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