Camera

Hgpovray

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Camera

##Access to camera information

These pieces of information are in read-only mode. You cannot use them to modify the actual value (no #declare or #local). The various vectors might have been updated by transform and look_at.

• camera_type is a string containing the type of the camera (but not its subtype, so cylinder camera might be ambiguous).
• camera_up is the actual up vector of the camera.
• camera_right is the actual right vector of the camera.
• camera_direction is the actual direction vector of the camera.
• camera_location is the actual location of the camera.

In case of scene with multiple cameras, each keyword can be followed by an usual array notation to access the relevant camera. (e.g. camera_up[3] for the fourth camera)

##Additional camera to map a planet

• position the camera as a satellite above the center point of the map (location)
• direction should point (relatively) to the center of the planet (location+direction == center)
• aspect ratio of output image should match the expected ratio of the projection, unless you want it otherwise for a stretched result

###aitoff_hammer

• ratio 2:1

###eckert_iv

• ratio 2:1

###eckert_vi

• ratio 2:1

###lambert_azimuthal

• ratio 1:1

###mercator

• ratio is up to you, it's impossible to reach the poles

###miller_cylindrical

• ratio 1.3638862 or 1:0.733

###mollweide

• ratio 2:1

###platecarree

• ratio 2:1

###van_der_grinten

• ratio 1:1

Cylindrical Equal Area Projection

• ratio formula is π.cos²(φ) with φ the standard parallel.

####balthasart

• ratio is about 1.3
• the standard parallel of the projection is 50°

####behrmann

• ratio is 3π:4 (about 2.36)
• the standard parallel of the projection is 30°

####edwards

• ratio is about 2
• the standard parallel of the projection is 37°24'

####gall

• ratio is π:2 or golden ratio (φ) (both near 1.6)
• the standard parallel of the projection is 45°

####hobo_dyer

• ratio is about 2
• the standard parallel of the projection is 37°30'

####lambert_cylindrical

• ratio is π
• the standard parallel of the projection is 0°

####peters

• ratio is about π:2 or golden ratio φ (not exactly the same thing, but around 1.6).
• the standard parallel of the projection is 44.138°.

####smyth_craster

• ratio is about 2
• the standard parallel of the projection is 37°04'

unfolding platonic

Of the 5 platonic solids, 4 are easy to unfold to make a map. The dodecahedron is not available so far.

####tetra

• ratio is about 2.886 ( 5:√3 )

####cube

• ratio is 2.5 ( 5:2 )

####octa

• ratio is about 2.3 ( 4:√3 )

####icosa

• ratio is about 2.1169 ( 11:3√3 )