The V-Ray Additional Attributes can be added to every Maya standard Camera by selecting the shape node of the camera and choosing the desired attributes from the Attributes>VRay Menu. Currently there are two different sets of extra attributes that you can add: Physical Camera and Camera Settings. The different settings of each are explained below.
The VRayPhysicalCamera allows you to use real-world parameters to set up the virtual CG camera (e.g. f-stop, lens focal length etc). It also makes it easier to use light sources with real-world illumination (e.g. VRayLight with physical units, or VRaySun and VRaySky). To use the V-Ray Physical camera attributes you need to add the Physical camera extra attributes to the Shape node of the camera. To do this select your camera and when on the shape node go to: Attributes>VRay>Physical camera.
Treat as VRay Physical camera - this option has to be selected in order to have the regular Maya camera act as a VRay Physical camera.
Type - determines the type of the camera. This mostly has an effect on the motion blur effect produced by the camera:
Still camera - simulates a still photo camera with a regular shutter.
Cinematic camera - simulates a motion-picture camera with a circular shutter.
Video camera - simulates a shutter-less video camera with a CCD matrix.
Film gate(in mm) - specifies the horizontal size of the film gate in millimeters. Note that this setting takes into account the system units configuration to produce the correct result.
Focal length(in mm) - specifies the equivalent focal length of the camera lens. This setting takes into account the system units configuration to produce the correct result. Vertical film gate size is calculated by accounting image aspect ratio (vertical film size = horizontal film size / aspect ratio).
Specify FOV - when set to Specify this option allows you to manually set the field of view for the camera from the FOV parameter. When set to From Maya camera the field of view is determined by the settings of the Maya camera.
FOV - a value for the Field of View of the camera
Zoom factor - specifies a zoom factor. Values greater than 1.0 zoom into the image; values smaller than 1.0 zoom out. This is similar to a blow-up rendering of the image.
Distortion type - determines what formula is used to calculate the distortion for the camera
Quadratic - this is the default distortion type. It uses a simplified formula that is easier to calculate than the Cubic method.
Cubic - this is the distortion type used in some camera tracking programs like SynthEyes, Boujou etc. If you plan on using one of these programs, you should use the Cubic distortion type.
Lens file - an external .lens file is used to determine the distortion for the camera
Texture - a displacement map from Nuke can be used to determine the camera distortion
Distortion amount - specifies the distortion coefficient for the camera lens. A value of 0.0 means no distortion; positive values produce "barrel" distortion, while negative values produce "pillow" distortion.
Lens file - load a file that is going to be used to calculate the camera distortion. This is only available when the Distortion type is set to Lens file.
Distortion map - load the texture that is going to be used to determine the camera distortion. This is only available when the Distortion type is set to Texture.
F-Stop - determines the width of the camera aperture.
Lens shift - allows the simulation of shift lenses for 2-point perspective. Changing this parameter is similar to applying a Camera correction modifier.
Shutter speed - the shutter speed, in inverse seconds, for the still photographic camera. For example, shutter speed of 1/30 s corresponds to a value of 30 for this parameter.
Shutter angle - shutter angle (in degrees) for the cinematic camera.
Shutter offset - shutter offset (in degrees) for the cinematic camera.
Latency - CCD matrix latency, in seconds, for the video camera.
ISO - determines the film power (i.e. sensitivity). Smaller values make the image darker, while larger values make it brighter.
Specify focus - this allows you to specify a focus distance different from the camera target distance.
Focus distance - sets the focus distance of the camera.
Exposure color correction - when this option is on, the F-number, Shutter speed and ISO settings will affect the image brightness.
White balance - allows additional modification of the image output. Objects in the scene that have the specified color will appear white in the image. Note that only the color hue is taken into consideration; the brightness of the color is ignored.
Enable Vignetting - when this option is on, the optical vignetting effect of real-world cameras is simulated.
Vignetting amount - specify the amount of the vignetting effect, where 0.0 is no vignetting and 1.0 is normal vignetting.
Enable Bokeh effects - defines the shape of the camera aperture. When this option is off, perfectly circular aperture is simulated. When on, a polygonal aperture is simulated. This option has effect when depth-of field is enabled.
Number of blades - specifies the number of blades of the polygonal aperture.
Blades rotation (in radians) - defines the rotation of the blades.
Center bias - defines a bias shape for the bokeh effects. Positive values make the outer edge of the bokeh effects brighter; negative values make the center of the effect brighter.
Bokeh anisotropy - allows stretching of the bokeh effect horizontally or vertically to simulate anamorphic lenses.
Enable Depth-of-field - turns on depth of field sampling.
Enable Motion blur - turns on motion blur sampling.
Subdivs - determines the number of samples (rays) for calculating depth of field and/or motion blur.
The Camera Settings Additional Attributes allow you to override some of the camera settings specified in the Camera roll-out of the V-Ray tab in the Render Settings dialog. This way you can have different camera settings for each camera in the scene. The options here control the way the geometry is projected onto the image. To use the Camera Settings attributes you need to add them to the Shape node of the camera. To do this select your camera and when on the shape node go to: Attributes>VRay>Camera Settings.
Override Global Camera Settings - overrides the global camera settings for the current camera. Must be checked in order for the next settings to have an effect.
Type - The cameras in V-Ray generally define the rays that are cast into the scene, which essentially is how the scene is projected onto the screen. V-Ray supports several camera types: Standard, Spherical, Cylindrical (point), Cylindrical (ortho), Box and Fish eye. Orthographic views are supported too. From this list you can select the type of the camera. See the Examples section for a more detailed discussion on camera types.
Standard - this is a standard pinhole camera.
Spherical - this is a spherical camera which means that the camera lenses has spherical form.
Cylindrical (point) - with this type of camera all rays have a common origin - they are cast from the center of the cylinder. In the vertical direction the camera acts as a pinhole camera and in the horizontal direction it acts as a spherical camera.
Cylindrical (ortho) - in vertical direction the camera acts as an orthographic view and in the horizontal direction it acts as a spherical camera.
Box - the box camera is simply 6 standard cameras placed on the sides of a box. This type of camera is excellent for generation of environment maps for cube mapping. It may be very useful for GI too - you can calculate the irradiance map with a Box camera, save it to file and you can reuse it with a Standard camera that can be pointed at any direction.
Fish eye - this special type of camera captures the scene as if it is normal pinhole camera pointed at an absolutely reflective sphere which reflects the scene into the camera's shutter. You can use the Dist/FOV settings to control what part of the sphere will be captured by the camera. The red arc in the diagram corresponds to the FOV angle. Note that the sphere always has a radius of 1.0.
Warped spherical - another spherical camera with slightly different mapping formula.
Override FOV - with this setting you can override Maya's FOV angle. This is because some V-Ray camera types can take FOV ranges from 0 to 360 degrees, whereas the cameras in Maya® are limited to 180 degrees.
FOV - here you specify the FOV angle (only when Override FOV is turned on and the current camera type supports FOV angle).
Height - here you can specify the height of the Cylindrical (ortho) camera. This setting is available only when the Type is set to Cylindrical (ortho).
Auto-fit - this setting controls the auto-fit option of the Fish-eye camera. When Auto-fit is enabled V-Ray will calculate the Dist value automatically so that the rendered image fits horizontally with the image's dimensions.
Dist - this setting applies only to the Fish-eye camera. The Fish-eye camera is simulated as a Standard camera pointed to an absolutely reflective sphere (with a radius of 1.0) that reflects the scene into the camera's shutter. The Dist value controls how far the camera is from the sphere's center (which is how much of the sphere will be captured by the camera). Note: this setting has no effect when the Auto-fit option is enabled.
Curve - this setting applies only to the Fish-eye camera. This setting contorts the way the rendered image is warped. A value of 1.0 corresponds to a real world Fish-eye camera. As the value approaches 0.0 the warping is increased. As the value approaches 2.0 the warping is reduced. Note: in fact this value controls the angle at which rays are reflected by the virtual sphere of the camera.
These extra attributes turn a normal camera into a VRayDomeCamera.
Treat as VRay Dome Camera - enables the VRayDomeCamera
Flip X - flips the view around the X axis
Flip Y - flips the view around the Y axis
FOV - specifies the field of view for the VRayDomeCamera
- There are three types of FoV (field of view): horizontal, vertical and diagonal. Horizontal FoV depends on the film gate size, focal length, focus distance and zoom factor. In addition to those four parameters, the vertical and diagonal FoV depend on the image aspect ratio.