3.7.6 finish.inc |
POV-Ray 3.6 for UNIX documentation 3.7.7 functions.inc |
3.7.8 glass.inc, glass_old.inc |
This include file contains interfaces to internal functions as well as several predefined functions. The ID's used to access the internal functions through calls to "internal(XX)", are not guaranteed to stay the same between POV-Ray versions, so users are encouraged to use the functions declared here.
The number of required parameters and what they control are also given in the include file, this chapter gives more
information.
For starter values of the parameters, check the "i_internal.pov" demo file.
Syntax to be used:
#include "functions.inc" isosurface { function { f_torus_gumdrop(x,y,z, P0) } ... } pigment { function { f_cross_ellipsoids(x,y,z, P0, P1, P2, P3) } COLOR_MAP ... )
Some special parameters are found in several of these functions. These are described in the next section and later referred to as "Cross section type", "Field Strength", "Field Limit", "SOR" parameters.
Cross Section Type:
In the helixes
and spiral functions, the 9th parameter is the cross section type.
Some shapes are:
0
:
0.0 to 1.0
:
1
:
1.0 to 2.0
:
2
:
2.0 to 3.0
:
3
:
The numerical value at a point in space generated by the function is multiplied by the Field Strength. The set of
points where the function evaluates to zero are unaffected by any positive value of this parameter, so if you are just
using the function on its own with threshold = 0, the generated surface is still the same.
In some cases, the
field strength has a considerable effect on the speed and accuracy of rendering the surface. In general, increasing
the field strength speeds up the rendering, but if you set the value too high the surface starts to break up and may
disappear completely.
Setting the field strength to a negative value produces the inverse of the surface, like
making the function negative.
This will not make any difference to the generated surface if you are using threshold that is within the field
limit (and will kill the surface completely if the threshold is greater than the field limit). However, it may make a
huge difference to the rendering times.
If you use the function to generate a pigment, then all points that are a
long way from the surface will have the same color, the color that corresponds to the numerical value of the field
limit.
If greater than zero, the curve is swept out as a surface of revolution (SOR).
If the value is zero or
negative, the curve is extruded linearly in the Z direction.
If the SOR switch is on, then the curve is shifted this distance in the X direction before being swept out.
If the SOR switch is on, then the curve is rotated this number of degrees about the Z axis before being swept out.
Sometimes, when you render a surface, you may find that you get only the shape of the container. This could be
caused by the fact that some of the build in functions are defined inside out.
We can invert the isosurface by
negating the whole function: -(function) - threshold
Here is a list of the internal functions in the order they appear in the "functions.inc" include file
f_algbr_cyl1(x,y,z, P0, P1, P2, P3, P4)
. An algebraic cylinder is what you get if you take any 2d
curve and plot it in 3d. The 2d curve is simply extruded along the third axis, in this case the z axis.
With the
SOR Switch switched on, the figure-of-eight curve will be rotated around the Y axis instead of being extruded along
the Z axis.
P0
: Field Strength
P1
: Field Limit
P2
: SOR Switch
P3
: SOR Offset
P4
: SOR Angle
f_algbr_cyl2(x,y,z, P0, P1, P2, P3, P4)
. An algebraic cylinder is what you get if you take any 2d
curve and plot it in 3d. The 2d curve is simply extruded along the third axis, in this case the z axis.
With the
SOR Switch switched on, the cross section curve will be rotated around the Y axis instead of being extruded along the
Z axis.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Field Limit
P2
: SOR Switch
P3
: SOR Offset
P4
: SOR Angle
f_algbr_cyl3(x,y,z, P0, P1, P2, P3, P4)
. An algebraic cylinder is what you get if you take any 2d
curve and plot it in 3d. The 2d curve is simply extruded along the third axis, in this case the Z axis.
With the
SOR Switch switched on, the cross section curve will be rotated around the Y axis instead of being extruded along the
Z axis.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Field Limit
P2
: SOR Switch
P3
: SOR Offset
P4
: SOR Angle
f_algbr_cyl4(x,y,z, P0, P1, P2, P3, P4)
. An algebraic cylinder is what you get if you take any 2d
curve and plot it in 3d. The 2d curve is simply extruded along the third axis, in this case the z axis.
With the
SOR Switch switched on, the cross section curve will be rotated around the Y axis instead of being extruded along the
Z axis.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Field Limit
P2
: SOR Switch
P3
: SOR Offset
P4
: SOR Angle
f_bicorn(x,y,z, P0, P1)
. The surface is a surface of revolution.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Scale. The mathematics of this surface suggest that the shape should be different for different
values of this parameter. In practice the difference in shape is hard to spot. Setting the scale to 3 gives a surface
with a radius of about 1 unit
f_bifolia(x,y,z, P0, P1)
. The bifolia surface looks something like the top part of a a paraboloid
bounded below by another paraboloid.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Scale. The surface is always the same shape. Changing this parameter has the same effect as
adding a scale modifier. Setting the scale to 1 gives a surface with a radius of about 1 unit
f_blob(x,y,z, P0, P1, P2, P3, P4)
. This function generates blobs that are similar to a CSG blob with
two spherical components. This function only seems to work with negative threshold settings.
P0
: X distance between the two components
P1
: Blob strength of component 1
P2
: Inverse blob radius of component 1
P3
: Blob strength of component 2
P4
: Inverse blob radius of component 2
f_blob2(x,y,z, P0, P1, P2, P3)
. The surface is similar to a CSG blob with two spherical components.
P0
: Separation. One blob component is at the origin, and the other is this distance away on the X
axis
P1
: Inverse size. Increase this to decrease the size of the surface
P2
: Blob strength
P3
: Threshold. Setting this parameter to 1 and the threshold to zero has exactly the same effect as
setting this parameter to zero and the threshold to -1
f_boy_surface(x,y,z, P0, P1)
. For this surface, it helps if the field strength is set low, otherwise
the surface has a tendency to break up or disappear entirely. This has the side effect of making the rendering times
extremely long.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Scale. The surface is always the same shape. Changing this parameter has the same effect as
adding a scale modifier
f_comma(x,y,z, P0)
. The 'comma' surface is very much like a comma-shape.
P0
: Scale
f_cross_ellipsoids(x,y,z, P0, P1, P2, P3)
. The 'cross ellipsoids' surface is like the union of three
crossed ellipsoids, one oriented along each axis.
P0
: Eccentricity. When less than 1, the ellipsoids are oblate, when greater than 1 the ellipsoids
are prolate, when zero the ellipsoids are spherical (and hence the whole surface is a sphere)
P1
: Inverse size. Increase this to decrease the size of the surface
P2
: Diameter. Increase this to increase the size of the ellipsoids
P3
: Threshold. Setting this parameter to 1 and the threshold to zero has exactly the same effect as
setting this parameter to zero and the threshold to -1
f_crossed_trough(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_cubic_saddle(x,y,z, P0)
. For this surface, it helps if the field strength is set quite low,
otherwise the surface has a tendency to break up or disappear entirely.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_cushion(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_devils_curve(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a negated function)
f_devils_curve_2d(x,y,z, P0, P1, P2, P3, P4, P5)
. The f_devils_curve_2d
curve can be
extruded along the z axis, or using the SOR parameters it can be made into a surface of revolution. The X and Y
factors control the size of the central feature.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: X factor
P2
: Y factor
P3
: SOR Switch
P4
: SOR Offset
P5
: SOR Angle
f_dupin_cyclid(x,y,z, P0, P1, P2, P3, P4, P5)
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Major radius of torus
P2
: Minor radius of torus
P3
: X displacement of torus
P4
: Y displacement of torus
P5
: Radius of inversion
f_ellipsoid(x,y,z, P0, P1, P2)
. f_ellipsoid
generates spheres and ellipsoids. Needs
"threshold 1".
Setting these scaling parameters to 1/n gives exactly the same effect as performing a
scale operation to increase the scaling by n in the corresponding direction.
P0
: X scale (inverse)
P1
: Y scale (inverse)
P2
: Z scale (inverse)
f_enneper(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_flange_cover(x,y,z, P0, P1, P2, P3)
P0
: Spikiness. Set this to very low values to increase the spikes. Set it to 1 and you get a sphere
P1
: Inverse size. Increase this to decrease the size of the surface. (The other parameters also
drastically affect the size, but this parameter has no other effects)
P2
: Flange. Increase this to increase the flanges that appear between the spikes. Set it to 1 for
no flanges
P3
: Threshold. Setting this parameter to 1 and the threshold to zero has exactly the same effect as
setting this parameter to zero and the threshold to -1
f_folium_surface(x,y,z, P0, P1, P2)
. A 'folium surface' looks something like a paraboloid glued to a
plane.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Neck width factor - the larger you set this, the narrower the neck where the paraboloid meets
the plane
P2
: Divergence - the higher you set this value, the wider the paraboloid gets
f_folium_surface_2d(x,y,z, P0, P1, P2, P3, P4, P5)
. The f_folium_surface_2d
curve can be
rotated around the X axis to generate the same 3d surface as the f_folium_surface
, or it can be extruded
in the Z direction (by switching the SOR switch off)
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Neck width factor - same as the 3d surface if you are revolving it around the Y axis
P2
: Divergence - same as the 3d surface if you are revolving it around the Y axis
P3
: SOR Switch
P4
: SOR Offset
P5
: SOR Angle
f_glob(x,y,z, P0)
. One part of this surface would actually go off to infinity if it were not
restricted by the contained_by shape.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_heart(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_helical_torus(x,y,z, P0, P1, P2, P3, P4, P5, P6, P7, P8, P9)
. With some sets of parameters, it looks
like a torus with a helical winding around it. The winding optionally has grooves around the outside.
P0
: Major radius
P1
: Number of winding loops
P2
: Twistiness of winding. When zero, each winding loop is separate. When set to one, each loop
twists into the next one. When set to two, each loop twists into the one after next
P3
: Fatness of winding?
P4
: Threshold. Setting this parameter to 1 and the threshold to zero has s similar effect as
setting this parameter to zero and the threshold to 1
P5
: Negative minor radius? Reducing this parameter increases the minor radius of the central torus.
Increasing it can make the torus disappear and be replaced by a vertical column. The value at which the surface
switches from one form to the other depends on several other parameters
P6
: Another fatness of winding control?
P7
: Groove period. Increase this for more grooves
P8
: Groove amplitude. Increase this for deeper grooves
P9
: Groove phase. Set this to zero for symmetrical grooves
f_helix1(x,y,z, P0, P1, P2, P3, P4, P5, P6)
P0
: Number of helixes - e.g. 2 for a double helix
P1
: Period - is related to the number of turns per unit length
P2
: Minor radius (major radius > minor radius)
P3
: Major radius
P4
: Shape parameter. If this is greater than 1 then the tube becomes fatter in the y direction
P5
: Cross section type
P6
: Cross section rotation angle (degrees)
f_helix2(x,y,z, P0, P1, P2, P3, P4, P5, P6)
. Needs a negated function
P0
: Not used
P1
: Period - is related to the number of turns per unit length
P2
: Minor radius (minor radius > major radius)
P3
: Major radius
P4
: Not used
P5
: Cross section type
P6
: Cross section rotation angle (degrees)
f_hex_x(x,y,z, P0)
. This creates a grid of hexagonal cylinders stretching along the z-axis. The
fatness is controlled by the threshold value. When this value equals 0.8660254 or cos(30) the sides will touch,
because this is the distance between centers. Negating the function will inverse the surface and create a honey-comb
structure. This function is also useful as pigment function.
P0
: No effect (but the syntax requires at least one parameter)
f_hex_y(x,y,z, P0)
. This is function forms a lattice of infinite boxes stretching along the z-axis.
The fatness is controlled by the threshold value. These boxes are rotated 60 degrees around centers, which are
0.8660254 or cos(30) away from each other. This function is also useful as pigment function.
P0
: No effect (but the syntax requires at least one parameter)
f_hetero_mf(x,y,z, P0, P1, P2, P3, P4, P5)
. f_hetero_mf (x,0,z)
makes multifractal height
fields and patterns of '1/f' noise
'Multifractal' refers to their characteristic of having a fractal dimension
which varies with altitude. Built from summing noise of a number of frequencies, the hetero_mf parameters determine
how many, and which frequencies are to be summed.
An advantage to using these instead of a height_field {} from an
image (a number of height field programs output multifractal types of images) is that the hetero_mf function domain
extends arbitrarily far in the x and z directions so huge landscapes can be made without losing resolution or having
to tile a height field. Other functions of interest are f_ridged_mf
and f_ridge
.
P0
: H is the negative of the exponent of the basis noise frequencies used in building these
functions (each frequency f's amplitude is weighted by the factor f - H ). In landscapes, and many natural forms, the
amplitude of high frequency contributions are usually less than the lower frequencies. P1
: Lacunarity' is the multiplier used to get from one 'octave' to the next. This parameter affects
the size of the frequency gaps in the pattern. Make this greater than 1.0
P2
: Octaves is the number of different frequencies added to the fractal. Each 'Octave' frequency is
the previous one multiplied by 'Lacunarity', so that using a large number of octaves can get into very high
frequencies very quickly.
P3
: Offset is the 'base altitude' (sea level) used for the heterogeneous scaling
P4
: T scales the 'heterogeneity' of the fractal. T=0 gives 'straight 1/f' (no heterogeneous
scaling). T=1 suppresses higher frequencies at lower altitudes
P5
: Generator type used to generate the noise3d. 0, 1, 2 and 3 are legal values.
f_hunt_surface(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_hyperbolic_torus(x,y,z, P0, P1, P2)
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Major radius: separation between the centers of the tubes at the closest point
P2
: Minor radius: thickness of the tubes at the closest point
f_isect_ellipsoids(x,y,z, P0, P1, P2, P3)
. The 'isect ellipsoids' surface is like the intersection of
three crossed ellipsoids, one oriented along each axis.
P0
: Eccentricity. When less than 1, the ellipsoids are oblate, when greater than 1 the ellipsoids
are prolate, when zero the ellipsoids are spherical (and hence the whole surface is a sphere)
P1
: Inverse size. Increase this to decrease the size of the surface
P2
: Diameter. Increase this to increase the size of the ellipsoids
P3
: Threshold. Setting this parameter to 1 and the threshold to zero has exactly the same effect as
setting this parameter to zero and the threshold to -1
f_kampyle_of_eudoxus(x,y,z, P0, P1, P2)
. The 'kampyle of eudoxus' is like two infinite planes with a
dimple at the center.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Dimple: When zero, the two dimples punch right through and meet at the center. Non-zero values
give less dimpling
P2
: Closeness: Higher values make the two planes become closer
f_kampyle_of_eudoxus_2d(x,y,z, P0, P1, P2, P3, P4, P5)
The 2d curve that generates the above surface
can be extruded in the Z direction or rotated about various axes by using the SOR parameters.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Dimple: When zero, the two dimples punch right through and meet at the center. Non-zero values
give less dimpling
P2
: Closeness: Higher values make the two planes become closer
P3
: SOR Switch
P4
: SOR Offset
P5
: SOR Angle
f_klein_bottle(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_kummer_surface_v1(x,y,z, P0)
. The Kummer surface consists of a collection of radiating rods.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_kummer_surface_v2(x,y,z, P0, P1, P2, P3)
. Version 2 of the kummer surface only looks like radiating
rods when the parameters are set to particular negative values. For positive values it tends to look rather like a
superellipsoid.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Rod width (negative): Setting this parameter to larger negative values increases the diameter
of the rods
P2
: Divergence (negative): Setting this number to -1 causes the rods to become approximately
cylindrical. Larger negative values cause the rods to become fatter further from the origin. Smaller negative numbers
cause the rods to become narrower away from the origin, and have a finite length
P3
: Influences the length of half of the rods. Changing the sign affects the other half of the
rods. 0 has no effect
f_lemniscate_of_gerono(x,y,z, P0)
. The "Lemniscate of Gerono" surface is an hourglass shape.
Two teardrops with their ends connected.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_lemniscate_of_gerono_2d(x,y,z, P0, P1, P2, P3, P4, P5)
. The 2d version of the Lemniscate can be
extruded in the Z direction, or used as a surface of revolution to generate the equivalent of the 3d version, or
revolved in different ways.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Size: increasing this makes the 2d curve larger and less rounded
P2
: Width: increasing this makes the 2d curve fatter
P3
: SOR Switch
P4
: SOR Offset
P5
: SOR Angle
f_mesh1(x,y,z, P0, P1, P2, P3, P4)
The overall thickness of the threads is controlled by the
isosurface threshold, not by a parameter. If you render a mesh1 with zero threshold, the threads have zero thickness
and are therefore invisible. Parameters P2 and P4 control the shape of the thread relative to this threshold
parameter.
P0
: Distance between neighboring threads in the x direction
P1
: Distance between neighboring threads in the z direction
P2
: Relative thickness in the x and z directions
P3
: Amplitude of the weaving effect. Set to zero for a flat grid
P4
: Relative thickness in the y direction
f_mitre(x,y,z, P0)
. The 'Mitre' surface looks a bit like an ellipsoid which has been nipped at each
end with a pair of sharp nosed pliers.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_nodal_cubic(x,y,z, P0)
. The 'Nodal Cubic' is something like what you would get if you were to
extrude the Stophid2D curve along the X axis and then lean it over.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_noise_generator(x,y,z, P0)
P0
: Noise generator number
f_odd(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_ovals_of_cassini(x,y,z, P0, P1, P2, P3)
. The Ovals of Cassini are a generalization of the torus
shape.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Major radius - like the major radius of a torus
P2
: Filling. Set this to zero, and you get a torus. Set this to a higher value and the hole in the
middle starts to heal up. Set it even higher and you get an ellipsoid with a dimple
P3
: Thickness. The higher you set this value, the plumper is the result
f_paraboloid(x,y,z, P0)
. This paraboloid is the surface of revolution that you get if you rotate a
parabola about the Y axis.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_parabolic_torus(x,y,z, P0, P1, P2)
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Major radius
P2
: Minor radius
f_ph(x,y,z)
= atan2( sqrt( x*x + z*z ), y )
When used alone, the "PH" function gives a
surface that consists of all points that are at a particular latitude, i.e. a cone. If you use a threshold of zero
(the default) this gives a cone of width zero, which is invisible. Also look at f_th
and f_r
f_pillow(x,y,z, P0)
P0
: Field Strength
f_piriform(x,y,z, P0)
. The piriform surface looks rather like half a lemniscate.
P0
: Field Strength
f_piriform_2d(x,y,z, P0, P1, P2, P3, P4, P5, P6)
. The 2d version of the "Piriform" can be
extruded in the Z direction, or used as a surface of revolution to generate the equivalent of the 3d version.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Size factor 1: increasing this makes the curve larger
P2
: Size factor 2: making this less negative makes the curve larger but also thinner
P3
: Fatness: increasing this makes the curve fatter
P4
: SOR Switch
P5
: SOR Offset
P6
: SOR Angle
f_poly4(x,y,z, P0, P1, P2, P3, P4)
. This f_poly4
can be used to generate the surface of
revolution of any polynomial up to degree 4.
To put it another way: If we call the parameters A, B, C, D, E; then
this function generates the surface of revolution formed by revolving "x = A + By + Cy2 + Dy3 + Ey4" around
the Y axis.
P0
: Constant
P1
: Y coefficient
P2
: Y2 coefficient
P3
: Y3 coefficient
P4
: Y4 coefficient
f_polytubes(x,y,z, P0, P1, P2, P3, P4, P5)
. The 'Polytubes' surface consists of a number of tubes.
Each tube follows a 2d curve which is specified by a polynomial of degree 4 or less. If we look at the parameters,
then this function generates "P0" tubes which all follow the equation " x = P1 + P2y + P3y2 + P4y3 +
P5y4 " arranged around the Y axis.
This function needs a positive threshold (fatness of the tubes).
P0
: Number of tubes
P1
: Constant
P2
: Y coefficient
P3
: Y2 coefficient
P4
: Y3 coefficient
P5
: Y4 coefficient
f_quantum(x,y,z, P0)
. It resembles the shape of the electron density cloud for one of the d orbitals.
P0
: Not used, but required
f_quartic_paraboloid(x,y,z, P0)
. The 'Quartic Paraboloid' is similar to a paraboloid, but has a
squarer shape.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_quartic_saddle(x,y,z, P0)
. The 'Quartic saddle' is similar to a saddle, but has a squarer shape.
P0
: Field Strength
f_quartic_cylinder(x,y,z, P0, P1, P2)
. The 'Quartic cylinder' looks a bit like a cylinder that is
swallowed an egg.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Diameter of the "egg"
P2
: Controls the width of the tube and the vertical scale of the "egg"
f_r(x,y,z)
= sqrt( x*x + y*y + z*z )
When used alone, the "R" function gives a surface
that consists of all the points that are a specific distance (threshold value) from the origin, i.e. a sphere. Also
look at f_ph
and f_th
f_ridge(x,y,z, P0, P1, P2, P3, P4, P5)
. This function is mainly intended for modifying other surfaces
as you might use a height field or to use as pigment function. Other functions of interest are f_hetero_mf
and f_ridged_mf
.
P0
: Lambda
P1
: Octaves
P2
: Omega
P3
: Offset
P4
: Ridge
P5
: Generator type used to generate the noise3d. 0, 1, 2 and 3 are legal values.
f_ridged_mf(x,y,z, P0, P1, P2, P3, P4, P5)
. The "Ridged Multifractal" surface can be used to
create multifractal height fields and patterns. 'Multifractal' refers to their characteristic of having a fractal
dimension which varies with altitude. They are built from summing noise of a number of frequencies. The f_ridged_mf
parameters determine how many, and which frequencies are to be summed, and how the different frequencies are weighted
in the sum.
An advantage to using these instead of a height_field{}
from an image is that the
ridged_mf function domain extends arbitrarily far in the x and z directions so huge landscapes can be made without
losing resolution or having to tile a height field. Other functions of interest are f_hetero_mf
and f_ridge
.
P0
: H is the negative of the exponent of the basis noise frequencies used in building these
functions (each frequency f's amplitude is weighted by the factor fE- H ). When H is 1, the fractalization is
relatively smooth. As H nears 0, the high frequencies contribute equally with low frequencies
P1
: Lacunarity is the multiplier used to get from one "octave" to the next in the
"fractalization". P2
: Octaves is the number of different frequencies added to the fractal. Each octave frequency is
the previous one multiplied by "Lacunarity". So, using a large number of octaves can get into very high
frequencies very quickly
P3
: Offset gives a fractal whose fractal dimension changes from altitude to altitude. The high
frequencies at low altitudes are more damped than at higher altitudes, so that lower altitudes are smoother than
higher areas
P4
: Gain weights the successive contributions to the accumulated fractal result to make creases
stick up as ridges
P5
: Generator type used to generate the noise3d. 0, 1, 2 and 3 are legal values.
f_rounded_box(x,y,z, P0, P1, P2, P3)
. The Rounded Box is defined in a cube from <-1, -1, -1> to
<1, 1, 1>. By changing the " Scale" parameters, the size can be adjusted, without affecting the Radius
of curvature.
P0
: Radius of curvature. Zero gives square corners, 0.1 gives corners that match "sphere {0,
0.1}"
P1
: Scale x
P2
: Scale y
P3
: Scale z
f_sphere(x,y,z, P0)
P0
: radius of the sphere
f_spikes(x,y,z, P0, P1, P2, P3, P4)
P0
: Spikiness. Set this to very low values to increase the spikes. Set it to 1 and you get a sphere
P1
: Hollowness. Increasing this causes the sides to bend in more
P2
: Size. Increasing this increases the size of the object
P3
: Roundness. This parameter has a subtle effect on the roundness of the spikes
P4
: Fatness. Increasing this makes the spikes fatter
f_spikes_2d(x,y,z, P0, P1, P2, P3)
=2-D function : f = f( x, z ) - y
P0
: Height of central spike
P1
: Frequency of spikes in the X direction
P2
: Frequency of spikes in the Z direction
P3
: Rate at which the spikes reduce as you move away from the center
f_spiral(x,y,z, P0, P1, P2, P3, P4, P5)
P0
: Distance between windings
P1
: Thickness
P2
: Outer diameter of the spiral. The surface behaves as if it is contained_by a sphere of this
diameter
P3
: Not used
P4
: Not used
P5
: Cross section type
f_steiners_roman(x,y,z, P0)
. The "Steiners Roman" is composed of four identical triangular
pads which together make up a sort of rounded tetrahedron. There are creases along the X, Y and Z axes where the pads
meet.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_strophoid(x,y,z, P0, P1, P2, P3)
. The "Strophoid" is like an infinite plane with a bulb
sticking out of it.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Size of bulb. Larger values give larger bulbs. Negative values give a bulb on the other side of
the plane
P2
: Sharpness. When zero, the bulb is like a sphere that just touches the plane. When positive,
there is a crossover point. When negative the bulb simply bulges out of the plane like a pimple
P3
: Flatness. Higher values make the top end of the bulb fatter
f_strophoid_2d(x,y,z, P0, P1, P2, P3, P4, P5, P6)
. The 2d strophoid curve can be extruded in the Z
direction or rotated about various axes by using the SOR parameters.
P0
: Field Strength
P1
: Size of bulb. Larger values give larger bulbs. Negative values give a bulb on the other side of
the plane
P2
: Sharpness. When zero, the bulb is like a sphere that just touches the plane. When positive,
there is a crossover point. When negative the bulb simply bulges out of the plane like a pimple
P3
: Fatness. Higher values make the top end of the bulb fatter
P4
: SOR Switch
P5
: SOR Offset
P6
: SOR Angle
f_superellipsoid(x,y,z, P0, P1)
. Needs a negative field strength or a negated function.
P0
: east-west exponentx
P1
: north-south exponent
f_th(x,y,z)
= atan2( x, z ) f_th()
is a function that is only useful when combined
with other surfaces.
It produces a value which is equal to the "theta" angle, in radians, at any point.
The theta angle is like the longitude coordinate on the Earth. It stays the same as you move north or south, but
varies from east to west. Also look at f_ph
and f_r
f_torus(x,y,z, P0, P1)
P0
: Major radius
P1
: Minor radius
f_torus2(x,y,z, P0, P1, P2)
. This is different from the f_torus function which just has the major and
minor radii as parameters.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Major radius
P2
: Minor radius
f_torus_gumdrop(x,y,z, P0)
. The "Torus Gumdrop" surface is something like a torus with a
couple of gumdrops hanging off the end.
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_umbrella(x,y,z, P0)
P0
: Field Strength (Needs a negative field strength or a
negated function)
f_witch_of_agnesi(x,y,z, P0, P1, P2, P3, P4, P5)
. The "Witch of Agnesi" surface looks
something like a witches hat.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Controls the width of the spike. The height of the spike is always about 1 unit
f_witch_of_agnesi_2d(x,y,z, P0, P1, P2, P3, P4, P5)
. The 2d version of the "Witch of Agnesi"
curve can be extruded in the Z direction or rotated about various axes by use of the SOR parameters.
P0
: Field Strength (Needs a negative field strength or a
negated function)
P1
: Controls the size of the spike
P2
: Controls the height of the spike
P3
: SOR Switch
P4
: SOR Offset
P5
: SOR Angle
eval_pigment(Pigm, Vect)
, This macro evaluates the color of a pigment at a specific point. Some
pigments require more information than simply a point, slope pattern based pigments for example, and will not work
with this macro. However, most pigments will work fine.
Parameters:
Vect
= The point at which to evaluate the pigment.
Pigm
= The pigment to evaluate.
f_snoise3d(x, y, z)
. Just like f_noise3d(), but returns values in the range [-1, 1].
f_sine_wave(val, amplitude, frequency)
. Turns a ramping waveform into a sine waveform.
f_scallop_wave(val, amplitude, frequency)
. Turns a ramping waveform into a "scallop_wave"
waveform.
Predefined pattern functions, useful for building custom function patterns or performing "displacement mapping" on isosurfaces. Many of them are not really useful for these purposes, they are simply included for completeness.
Some are not implemented at all because they require special parameters that must be specified in the definition, or information that is not available to pattern functions. For this reason, you probably would want to define your own versions of these functions.
All of these functions take three parameters, the XYZ coordinates of the point to evaluate the pattern at.
f_agate(x, y, z)
f_boxed(x, y, z)
f_bozo(x, y, z)
f_brick(x, y, z)
f_bumps(x, y, z)
f_checker(x, y, z)
f_crackle(x, y, z)
f_cylindrical(x, y, z)
f_dents(x, y, z)
f_gradientX(x, y, z)
f_gradientY(x, y, z)
f_gradientZ(x, y, z)
f_granite(x, y, z)
f_hexagon(x, y, z)
f_leopard(x, y, z)
f_mandel(x, y, z)
f_marble(x, y, z)
f_onion(x, y, z)
f_planar(x, y, z)
f_radial(x, y, z)
f_ripples(x, y, z)
f_spherical(x, y, z)
f_spiral1(x, y, z)
f_spiral2(x, y, z)
f_spotted(x, y, z)
f_waves(x, y, z)
f_wood(x, y, z)
f_wrinkles(x, y, z)
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