Sensors

Perspective camera — type="perspective"

A standard pinhole camera with an optional thin-lens depth-of-field model. The camera is defined inside a <sensor> element together with a <sampler> and a <film>.

Parameters

Name	Type	Default	Description
fov	float	45	Vertical field of view in degrees.
lookAt	transform	—	Camera position, target, and up vector (see below).
apertureRadius or aperture	float	0	Lens radius. 0 gives a pinhole with infinite depth of field.
focusDistance or focalDistance	float	1	Distance from the camera origin to the focal plane. Only has an effect when aperture > 0.

Film parameters (inside <film>)

Name	Type	Default	Description
width	integer	640	Image width in pixels.
height	integer	480	Image height in pixels.

Sampler parameters (inside <sampler>)

Name	Type	Default	Description
sampleCount	integer	1	Samples per pixel. Higher values reduce noise.

Camera orientation

The <lookAt> element inside <transform name="toWorld"> specifies the camera pose:

<transform name="toWorld">
    <lookAt origin="0, 2, 6" target="0, 0, 0" up="0, 1, 0"/>
</transform>

• origin — world-space position of the camera.
• target — point the camera is aimed at.
• up — world-space up vector (usually 0, 1, 0).

Example — pinhole

<sensor type="perspective">
    <float name="fov" value="40"/>
    <transform name="toWorld">
        <lookAt origin="0, 2, 5" target="0, 0, 0" up="0, 1, 0"/>
    </transform>
    <sampler type="independent">
        <integer name="sampleCount" value="128"/>
    </sampler>
    <film type="hdrfilm">
        <integer name="width"  value="1280"/>
        <integer name="height" value="720"/>
    </film>
</sensor>

Example — depth of field

Set apertureRadius to a positive value and focusDistance to the distance of the subject from the camera:

<sensor type="perspective">
    <float name="fov" value="35"/>
    <float name="apertureRadius" value="0.1"/>
    <float name="focusDistance"  value="6"/>
    <transform name="toWorld">
        <lookAt origin="0, 1.5, 8" target="0, 0.5, 0" up="0, 1, 0"/>
    </transform>
    <sampler type="independent">
        <integer name="sampleCount" value="256"/>
    </sampler>
    <film type="hdrfilm">
        <integer name="width"  value="1280"/>
        <integer name="height" value="720"/>
    </film>
</sensor>

Larger apertureRadius produces a shallower depth of field (more blur). Objects at exactly focusDistance metres from the camera origin are in sharp focus.