Graphics Programs Reference
In-Depth Information
3.
Set an aperture size to determine the amount
of blurring. This can be specified in terms of
either a radius or a number of F/Stops. Higher
numbers give more blur with radius or less with
F/Stops. For the Spider Bot, I used radius to set
the depth of field to about 0.3.
added an RGB Curves node before the Blur node to
increase the contrast and slightly darken the image
to be blurred.
For color grading, I added a Color Balance
node: I chose a purplish color for the Lift Color
and a greenish tint for the Gain. I set the Gamma
to slightly bluish and brightened up the highlights
of the image a bit by setting the value of the gain
slightly higher than 1.0. (You can set numerical val-
ues for the RGB or HSV colors for Lift, Gamma, and
Gain by clicking the color picker.) I then connected
the output of the Color Balance node to the image
socket Composite output node. The finished node
tree is shown in Figure 14-15 and the resulting com-
posite in Figure 14-16.
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Cycles can also mimic the shape of an aperture like the
one you might find on a real film or digital camera.
To do this, set Blades to the number of sides of the
aperture shape and set Rotation to rotate the shape.
When setting the distance for the depth of
field, you can either set a number manually with the
Depth setting or specify an object using the selec-
tor under Focus. This causes the camera to ignore
the Manual Depth setting and focus on the object's
center instead. It's usually easiest to create an empty
object, place it where you want the scene to be in
focus, and then set this empty object as the depth-
of-field target in the Camera settings.
To better visualize the depth-of-field distance,
enable the Limits option in the Display panel of the
Camera settings. Blender then displays a line point-
ing out from the camera (describing the clipping
distances) with a yellow cross at the depth-of-field
distance.
Rendering and Compositing the
Jungle Temple
The Jungle Temple was a complex scene, and
my Render settings had a much greater impact
on render times for this project. I set the render
size of the image to 2880×3840; the number of
Render Samples in the Sampling settings to 5000;
and Clamp to 3.0 to try to reduce noise a bit more
quickly.
*
Although 5000 samples is a lot, I wasn't particularly
Render Settings for the Spider Bot
With depth of field set up, I was ready to render.
I set the resolution of the render to 2600×3600,
and in the Integrator panel of the Render tab, I set
Render Samples to 1000 and Clamp to 2 to reduce
the number of fireflies in the scene.
I wanted light to bounce around my scene and
illuminate the shadows, but almost all of the scene
is in direct light, so I didn't need to rely on bounced
light too heavily. I set Max Bounces to 32 (with a
minimum of 4 to allow early termination) and the
three Light Paths settings to 32 as well. I didn't need
any render layers or extra passes, so I left the Layers
panel alone and pressed Render (F12).
concerned about how long my render took. Primarily,
this high number was necessary because there were a
lot of soft shadows in the scene. For good results with
fewer samples, you can try turning down the Size set-
ting on some of the lamps in your scene at the cost of
harder-edged shadows.
For bounces, I set the Max to 128 and Min
to 8 to allow for probabilistic ray termination.
Because I wanted to composite the final render on
a background image of clouds and sky, I turned on
Transparent under Film options.
I left the other Render options at their default
and pressed F12 to render.
Compositing the Spider Bot
Next, I added some color grading and bloom to my
final render. While Cycles provides some different
render passes, the process of compositing is essen-
tially the same as when using Blender Internal. I
added bloom as I did with the Bat Creature, using
a Blur node to blur the image and an Add node
to add the result back onto the image. Again, I
Background Required
When compositing the Jungle Temple, I wanted to
add bloom, depth of field, and some color grading.
But first I needed to composite my render over a
background, which meant creating a background in
GIMP and then importing it into Blender with an
Image Texture node for further compositing.
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