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Chapter 19: Configuring and Aiming Cameras

Camera Correction modifier
To understand the Camera Correction modifier, you first need to understand what two-point perspective is.
Default cameras in Max use three-point perspective, which causes all lines to converge to a vanishing point
off in the distance, but two-point perspective causes all vertical lines to remain vertical.
The visual effect of this modifier is that extra-tall objects appear to bend toward the camera when corrected.
For example, if you have a camera pointed at a skyscraper, then correcting the camera with the Camera
Correction modifier makes the top of the building appear closer rather than having it recede away.
The Camera Correction modifier has an Amount value that lets you specify how much correction to apply
and a Direction value that orients the angle of vertical lines in the scene. There is also a Guess button,
which automatically sets the correction values for you based on the Z-axis vertical.

Caution
The Camera Correction modifier doesn’t appear in the Modifier List in the Modifier Stack, but you can select it
from the Modifiers ➪ Cameras menu. n

Creating multi-pass camera effects
All cameras have the option to enable them to become multi-pass cameras. You can find these settings in
the Parameters rollout when a camera object is selected. Multi-pass cameras are created by checking the
Enable button and selecting the effect from the drop-down list. The current available effects include Depth
of Field (mental ray), Depth of Field, and Motion Blur. For each, an associated rollout of parameters opens.

Cross-Ref
The Depth of Field (mental ray) effect option is covered in Chapter 47, “Rendering with mental ray.” n
The Multi-Pass Effect section of the Parameters rollout also includes a Preview button. This button makes
the effect visible in the viewports for the current frame. This feature can save you a significant amount of
time that normally would be spent test-rendering the scene. The Preview button is worth its weight in ren-
der speed. Using this button, you can preview the effect without having to render the entire sequence.

Caution
The Preview button does not work unless the Camera view is the active viewport. n
The Render Effect Per Pass option causes any applied Render Effect to be applied at each pass. If disabled,
then any applied Render Effect is applied after the passes are completed.
Cross-Ref
You can also apply these multi-pass effects as Render Effects. See Chapter 46, “Using Atmospheric and Render
Effects.” n

Using the Depth of Field effect
The Depth of Field Parameters rollout, shown in Figure 19.6, appears when the Depth of Field option is
selected in the Multi-Pass Effect section of the Parameters rollout. It includes settings for controlling the
Depth of Field multi-pass effect.

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