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POV-Ray Introduction
Content - INDEX
0. Working with POV-Ray:
"Insert Menu Add-on".
1. Basics
on writing texts.
2. 3D Coordinates,
Floats and Vectors
3. Scene Structur
#include files,
camera,
light_source.
Types of light sources
4. Basic Objects plane, sphere,
box, cylinder, cone, torus.
Other Shapes
height_field, text, etc.
>5. Transformations
Streching, Turning,
Moving and others.
CSG: union,
difference, intersection.
6. Color + Surfaces
texture, pigment, normal, finish
7. #declare, #local,
#macro .. #end,
#include,
re-usable objects.
8. #while Loops
9. Efficiency,
speed, flexibility,
modulare working
adapting from 3.1 to 3.5;3.6
adapting from 3.5;3.6 to 3.7
POV-Ray + Windows Vista.
- Insert Menu Add-on
& Download
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V Scaling, Rotation, Translation
For more detailed informations on this item see my Tutorial "Geometric Transformations".
scaling, rotation, translation and transformation matrixes.
These transformations may be applied as well as on the geometrie of an object as on e.g. his texture or
on its texture components.
3.2.1 scale = scaling / resizing - enlarging or reducing in size -
The strechings are all defined relative to the center <0,0,0> or the axis or to the planes of the system of coordinates
Scaling causes a centric streching in the according direction of the coordinats relative to the center of the
system of coordinates (=<0,0,0>).
Samples:
scale 2 causes the same as scale<2,2,2>: the size of the shape grows in
all directions twice.
scale 0.5 in all directions together multiplied by 0.5 - this means: all reduced to its half
scale<1.0,0.5,3.0> different sizing in x- ,y- and z-direction.
Here: in x-direction original - no change, in y-direction reduced to the half and in z-direction increased to 3 times stretched.
scale<-1,1,1> mirrors an object at the yz-plane.
3.2.2 rotate / turning around -
The rotations are all defined relative to the axis of the system of coordinates!!
"rotate" causes a rotation according the "Left-thumb-rule" around the according axis
of the system of coordinates.
Sample: rotate<0,45,0> turns a shape around the y-axis by 45 degrees.
Attention:> The rotations are not applied relative of any local axes of symetriy through the center of an object but everytime relative to the
axes of the coordinate system.
Attention:The rotations will be applied in the writen order! Sequential rotations arround different axes
are not interchangeable!
3.2.3 translate
parallel moving relatively to a starting position
"translate" causes a translation (a parallel moving) without affecting the shape of an object.
Sample: translate <-2,1,3> moves the object by 2 steps to the left (-x-direction), by 1 step
upward (+y-direction) and by 3 steps ahead (+z-direction).
3.2.4 other transformations
Using the transformation matrix
it is possible to realize all the above mentioned transformations as well as
also much more complex affine transformations, e.g. shearing an object parallel
to a coordinate plane.
CSG (Constructiv Solid Geometry)
Boolean algebra with objects
Cut and paste and caving out by Boolean functions:
1.: union = unification of objects = connecting different objects to a new object
(merge = used instead of union for transparent objects, if the inner borders are not wanted to be visible.
2.: difference = the rest of 1.object minus 2.object minus 3.object etc.
3.: intersection = this means those parts of all objects, which they have common with all of each other
| Connect it! |
Subtract it! |
What's in both? |
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union{...}
oder merge{...} |
difference{...} |
intersection{...} |
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!!! Attention: The objects to be subtracted from another have to have no coincident surfaces.
It must reach unambiguous out of the first object. In the case of coincident surfaces
the precision of computer calculation will be the trap: sometimes the surface is subtracted,
sometimes it is not - and this will happen in an very unpredictable manner!
(This error may occur only in some locations of the camera - but then it will be very very boring!)
For details see: CSG - Constructiv Solid Geometry - Boolean Algebra with Solids.
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email:
Friedrich.Lohmueller_at_t-online.de