6.1.1  Identifiers and Keywords

POV-Ray allows you to define identifiers for later use in the scene file. An identifier may be 1 to 40 characters long. It may consist of upper and lower case letters, the digits 0 through 9 or an underscore character ("_"). the first character must be an alphabetic character. The declaration of identifiers is covered later.

POV-Ray has a number of reserved keywords which are listed below.

a
aa_level
aa_threshold
abs
absorption
accuracy
acos
acosh
adaptive
adc_bailout
agate
agate_turb
all
all_intersections
alpha
altitude
always_sample
ambient
ambient_light
angle
aperture
append
arc_angle
area_light
array
asc
ascii
asin
asinh
assumed_gamma
atan
atan2
atanh
autostop
average
b
b_spline
background
bezier_spline
bicubic_patch
black_hole
blob
blue
blur_samples
bounded_by
box
boxed
bozo
break
brick
brick_size
brightness
brilliance
bump_map
bump_size
bumps
c
camera
case
caustics
ceil
cells
charset
checker
chr
circular
clipped_by
clock
clock_delta
clock_on
collect
color
color_map
colour
colour_map
component
composite
concat
cone
confidence
conic_sweep
conserve_energy
contained_by
control0
control1
coords
cos
cosh
count
crackle
crand
cube
cubic
cubic_spline
cubic_wave
cutaway_textures
cylinder
cylindrical
d
debug
declare
default
defined
degrees
density
density_file
density_map
dents
df3
difference
diffuse
dimension_size
dimensions
direction
disc
dispersion
dispersion_samples
dist_exp
distance
div
double_illuminate
e
eccentricity
else
emission
end
error
error_bound
evaluate
exp
expand_thresholds
exponent
exterior
extinction
f
face_indices
facets
fade_color
fade_colour
fade_distance
fade_power
falloff
falloff_angle
false
fclose
file_exists
filter
final_clock
final_frame
finish
fisheye
flatness
flip
floor
focal_point
fog
fog_alt
fog_offset
fog_type
fopen
form
frame_number
frequency
fresnel
function
g
gather
gif
global_lights
global_settings
gradient
granite
gray
gray_threshold
green
h
height_field
hexagon
hf_gray_16
hierarchy
hypercomplex
hollow
i
if
ifdef
iff
ifndef
image_height
image_map
image_pattern
image_width
include
initial_clock
initial_frame
inside
inside_vector
int
interior
interior_texture
internal
interpolate
intersection
intervals
inverse
ior
irid
irid_wavelength
isosurface
j
jitter
jpeg
julia
julia_fractal
l
lambda
lathe
leopard
light_group
light_source
linear_spline
linear_sweep
ln
load_file
local
location
log
look_at
looks_like
low_error_factor
m
macro
magnet
major_radius
mandel
map_type
marble
material
material_map
matrix
max
max_extent
max_gradient
max_intersections
max_iteration
max_sample
max_trace
max_trace_level
media
media_attenuation
media_interaction
merge
mesh
mesh2
metallic
method
metric
min
min_extent
minimum_reuse
mod
mortar
n
natural_spline
nearest_count
no
no_bump_scale
no_image
no_reflection
no_shadow
noise_generator
normal
normal_indices
normal_map
normal_vectors
number_of_waves
o
object
octaves
off
offset
omega
omnimax
on
once
onion
open
orient
orientation
orthographic
p
panoramic
parallel
parametric
pass_through
pattern
perspective
pgm
phase
phong
phong_size
photons
pi
pigment
pigment_map
pigment_pattern
planar
plane
png
point_at
poly
poly_wave
polygon
pot
pow
ppm
precision
precompute
pretrace_end
pretrace_start
prism
prod
projected_through
pwr
q
quadratic_spline
quadric
quartic
quaternion
quick_color
quick_colour
quilted
r
radial
radians
radiosity
radius
rainbow
ramp_wave
rand
range
ratio
read
reciprocal
recursion_limit
red
reflection
reflection_exponent
refraction
render
repeat
rgb
rgbf
rgbft
rgbt
right
ripples
rotate
roughness
s
samples
save_file
scale
scallop_wave
scattering
seed
select
shadowless
sin
sine_wave
sinh
size
sky
sky_sphere
slice
slope
slope_map
smooth
smooth_triangle
solid
sor
spacing
specular
sphere
sphere_sweep
spherical
spiral1
spiral2
spline
split_union
spotlight
spotted
sqr
sqrt
statistics
str
strcmp
strength
strlen
strlwr
strupr
sturm
substr
sum
superellipsoid
switch
sys
t
t
tan
tanh
target
text
texture
texture_list
texture_map
tga
thickness
threshold
tiff
tightness
tile2
tiles
tolerance
toroidal
torus
trace
transform
translate
transmit
triangle
triangle_wave
true
ttf
turb_depth
turbulence
type
u
u
u_steps
ultra_wide_angle
undef
union
up
use_alpha
use_color
use_colour
use_index
utf8
uv_indices
uv_mapping
uv_vectors
v
v
v_steps
val
variance
vaxis_rotate
vcross
vdot
version
vertex_vectors
vlength
vnormalize
vrotate
vstr
vturbulence
w
warning
warp
water_level
waves
while
width
wood
wrinkles
write
x
x
y
y
yes
z
z

All reserved words are fully lower case. Therefore it is recommended that your identifiers contain at least one upper case character so it is sure to avoid conflict with reserved words.