_{Scene rendered with Spherical Camera lens}

This is a spherical camera which means that the camera lens has a spherical appearance. A common use of this camera projection is to allow the creation of environment maps (in spherical map format) for later use as reflection maps or for environment lighting. To get the full spherical range, the camera's screen window must be set to [-1,-1] to [1,1]. Note that the same mapping could be achieved in the cylindrical camera with careful setting of the Horizontal FOV, Vertical FOV, and Projective parameters but the spherical camera is provided for convenience.

• Position
• Look At
• Up
• Matrix
• Near Clip
• Far clip
• Shutter Start
• Shutter End
• Shutter Type
• Rolling Shutter
• Filtermap
• Handedness
• Screen Window Min
• Screen Window Max
• Exposure
  • Workflow Example

Position

The position of the camera.

Look At

The point at which the camera is pointing.

Up

The up vector of the camera.

Matrix

Matrix to define the position and orientation of the camera.

Near Clip

The near clipping plane of the camera's renderable area.

Far clip

The far clipping plane of the camera's renderable area.

Shutter Start

Defines when the camera shutter is open. Rays will have a time randomly assigned between Shutter Start and Shutter End. It is recommended that this time be frame-relative, that is if the current frame (set on the global options) is 1001, then Shutter Start can be -0.25 to signify a shutter opening one-quarter frame before the actual frame marker passes, while Shutter end would be 0.25 to close the shutter one-quarter frame after the frame passes. This would be centered motion blur. Other typical shutter values would be from 0.0 to 0.5 (lead-out motion blur), or even -0.5 to 0.0 (lead-in motion blur).

Info: The shutter range of the camera can be defined by changing the Shutter Start and Shutter End parameters. The value range should use the same time reference as the motion times. The default Shutter Start of 0 and Shutter End of 1 means a full camera shutter range equivalent to the default motion blur range. A smaller range (0.0-0.5) will decrease the effective shutter aperture time and only show the first half of the motion.

Shutter End

Defines when the camera shutter is closed. Please see Shutter Start for a detailed description of shutter semantics. The Shutter End must be larger than or equal to Shutter Start. If they are the same, this will ensure no motion blur is generated.

Shutter Type

The filtering applied to time samples. By default, this is a Box Filter, with all time samples having the same weight. A Triangle Filter (or "tent") is also available which produces smoother trails.

Arnold supports custom shutter shapes with the shutter curve camera parameter. You can define as many points as required. Coordinates increase from 0 (corresponding to the Shutter Start to 1 (corresponding to the Shutter End). Values in the vertical axis must be non-negative, and it is not recommended to enter values above 1. The values are linearly interpolated between each point. In the examples below, you can see the effect different curve shapes have on the motion blur trail of a sphere that has been key-framed moving from left to right.

Rolling Shutter

Rolling Shutter is used to simulate the type of rolling shutter effect seen in footage shot with digital cameras that use CMOS-based sensors such as Blackmagics, Alexas, REDs, and even iPhones. This method is implemented by rolling (moving) the shutter across the camera area instead of the entire image area all at the same time.

The Rolling Shutter direction specifies the direction that the rolling shutter takes place. The default is Off and can be set to Top (top to bottom being the most common scanning direction), Bottom, Left or Right.

Interesting effects can be achieved when combining motion blur 'length' with rolling shutter:

_{Motion blur length from 0 to 2}

Filtermap

Weights the camera sample by a scalar amount defined by the shader linked to the filtermap. This shader will use as an input, u,v coordinates in image-space coords (0,1) and x,y in pixel coordinates. This allows you to darken certain regions of the image, perfect to simulate vignetting effects.

There is an optimization in place where if the filter returns pure black then the camera ray is not fired. This can help in cases such as when rendering with the fisheye camera where, depending on its autocrop setting, parts of the frame trace no rays at all.

_{circular ramp mapped to the camera's filtermap to create a vignette effect}

Handedness

Chooses the 'right' handed or 'left' handed coordinate system.

Screen Window Min

This defines the 2d window in the projection plane that will be rendered. If set to its default (-1,-1) (1,1) the frame will exactly match with the defined region, after taking Aspect Ratio into account so that there is no distortion. These should be set if you want to stretch, squash, or zoom to a particular area in an image.

Screen Window Max

This defines the 2d window in the projection plane that will be rendered. If set to its default (-1,-1) (1,1) the frame will exactly match with the defined region, after taking aspect_ratio into account so that there is no distortion. These should be set if you want to stretch, squash, or zoom to a particular area in an image.

Exposure

Simulates the effect of camera exposure (in a non-physical way). Increasing this parameter by a value of one gives you one stop up (doubles the brightness).

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Workflow Example

Below is an example of a spherical camera lens. The image below shows a studio lighting rig scene. The Spherical Camera can be used to convert this scene into a 'spherical' HDRI that can be used with the Skydome Light.

• Position the camera in the center, in order to convert the scene into a spherical camera image.

_{Light texture maps have been assigned to the reflector planes (textured light sources will not be visible to the camera).}

The image below is a render of the spherical camera in the center of the scene. The scene must be rendered at a high enough resolution and the pixel aspect ratio should be set to 1, otherwise, distortions may appear in the reflections of the scene.