Tous les systèmes hamiltoniens intégrables se ressemblent, mais chacun qui est non intégrable, il est non intégrable à sa manière
DESCRIPTION
The vfplot (1) program with the --output-format povray option writes its output in the povray (1) format. This note describes
the use of these files.
OVERVIEW
The POV-Ray output of vfplot (1) consists of a number of arrow objects aligned in the xy-plane of POV-Ray's xyz coordinate system. The vfplot output does not contain any camera or light objects, these must be added by the user. The easiest way to do this is by writing a small file which sets the camera and lighting for the scene, and then includes the vfplot output.
The vfplot arrow object all have a z-value of
zero and have the lower-left corner of their extent at the POV-Ray origin. So the scene will be
bounded by [0, X] and [0, Y], and a
camera position of <X/2, Y/2, -d> will view the scene with
the x- and y-axes in their usual positions (at a distance d).
PARAMETERS
Several of the parameters determining the appearance of the scene objects can be adjusted by declaring them prior to the inclusion of the scene file:
vfplot_arrow_texture-
The texture used for the arrows.
vfplot_ellipse_texture-
The texture used for the bounding ellipses.
vfplot_domain_texture-
The texture used for the domain.
vfplot_domain_depth-
The domain is union of rectangular prisms, this parameter gives the depth (the z-extent) of the prism.
vfplot_network_texture-
The texture used for the neighbours network.
vfplot_network_node-
The network is a set of cylindrical rods with spherical nodes. This parameter is the ratio of the radius of the sphere the radius of the cylinder.
vfplot_edge_radius-
Several scene items can have rounded corners. This parameter controls the radius of the rounding relative to the size of the object being rounded. Values between 0.1 and 0.4 give good results.
The adventurous might like to rewrite the macros which describe the scene objects:
vfplot_clr-
A (left or right) curved arrow.
vfplot_s-
A straight arrow.
vfplot_e-
An ellipsiod.
vfplot_d-
A section of the domain.
vfplot_n-
A network edge and its nodes.
EXAMPLE
The following file includes the vfplot output file vfplot.inc
and provide a camera and light to illuminate the scene. It also redefines the edge radius and
arrow texture to produce a rounded, transparent and slightly shiny blue arrow
#version 3.5;
#include "colors.inc"
#declare CD = 130;
#declare MX = 144;
#declare MY = 86;
camera {
location <MX, MY, -CD>
look_at <MX, MY, 0>
}
light_source {
<0, 0, -CD>
color rgb 0.4
parallel
point_at <0, 0, 0>
}
background {
color rgb 0.9
}
#declare vfplot_edge_radius = 0.2;
#declare vfplot_arrow_texture =
texture {
pigment {
color Blue
transmit 0.7
}
finish {
phong 0.5
}
};
#include "vfplot.inc"