Geometry


  New   Stereo projection for hemispherical domes
Unity game engine and iDome
Data visualisation in crystal
Warping patch for Quartz Composer
FAQ: Spherical mirror projection for hemispherical domes

The contents of this web site are © Copyright Paul Bourke or a third party contributer where indicated. You may print or save an electronic copy of parts of this web site for your own personal use. Permission must be sought for any other use.


POV-Ray: A Tool for Creating Engaging Visualisation of Geometry

Various notes on polygons and meshes
Includes Surface (polygon) simplification, Clipping a polygonal facet with an arbitrary plane, Surface Relaxation and Smoothing of polygonal data, Mesh crumpling, splitting polygons, two sided facets, polygon types.

Philosophy is written in this grand book - I mean universe - which stands continuously open to our gaze, but which cannot be understood unless one first learns to comprehend the language in which it is written. It is written in the language of mathematics, and its characters are triangles, circles and other geometric figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering about in a dark labyrinth.
Galileo (1623)

Distance between a point, a line and a plane
The intersection of a line with another line (2D)
The closest line between two lines (3D)
The intersection of a line with a plane
Mathematics describing a plane
The intersection of two planes
The intersection of three planes
Polygon area and centroid calculation
Inside / outside polygon test
Reflection of a ray
Direction Cosines
Eulers number and closed surfaces
Determining whether a line segment intersects a facet
Coordinate transformations on the plane (2D)
Cartesian, Cylindrical, and Spherical
Euler angles and coordinate transformations
Converting between left and right coordinate systems

Clipping a line with a polygon
Clockwise test for polygons in 2D
Test for concave/convex polygon in 2D
Area of (planar) polygons in 3D
Spheres, equations and terminology
The intersection of a line and a sphere (or a circle)
Equation of the circle through 3 points
Equation of the sphere through 4 points
Intersecting area of circles on a plane
Rotation of a point about an arbitrary axis
Creating a plane/disk perpendicular to a line segment
Intersection of two circles on the plane
Circumference of an ellipse
Intersection of two spheres
Distributing Points on a Sphere
Quadric equations in x and y of degree 2
Fowler angles: Comparing angles without trigonometry

Contouring Algorithm
Description of an efficient contouring algorithm as it appeared in Byte magazine. (Byte Magazine, 1987) and a more general approach for arbitrary contour planes and polygonal meshes.

Spherical projections
Methods for mapping points on a spherical surface onto a plane, stereographic and cylindrical (including Mercator) projections. Includes Aitoff map projection: Conversion to/from longitude/latitude (spherical map)

Projection types
Classification of projections from 3D to 2D and specific examples of oblique projections.

A triangle was an improvement to the square wheel. It eliminated one bump.
BC comics

Planar (stretching) distortion in the plane

Anamorphic projections

Mappings in the complex plane
Otherwise known as Conformal maps

Polygonising a scalar field
Otherwise known as marching cubes and marching tetrahedrons.

HyperSpace (Historic)
A Macintosh 4 dimensional geometry viewer and manual.

There are holes in the sky. Where the rain gets in. But they're ever so small. That's why the rain is thin.
Spike Milligan

Waterman Polyhedra
Cylinder intersections
Plexagons (Pleated hexagon)
4D platonic solids
Polar Sphere

"We should make things as simple as possible, but not simpler."
Albert Einstein

Coordinates for 4D polyhedra
Polar + Star
Parallelohedron
Platonic solids
Time Star

To see a World in a Grain of Sand, And Heaven in a Wild Flower
Hold Infinity in the palm of your hand, And Eternity in an hour
William Blake

Photos by Gayla Chandler
Star Sphere
Build your own
80 Polyhedra
Cube personalities

If triangles had a God, He'd have three sides.
Old Yiddish proverb

Rhombic Triacontahedron
Polyhedra data files
Kissing number

Experience hath shewn, that even under the best forms of government those entrusted with power have, in time, and by slow operations, perverted it into tyranny.
Thomas Jefferson


  New   Stereo projection for hemispherical domes
Unity game engine and iDome
Data visualisation in crystal
Warping patch for Quartz Composer
FAQ: Spherical mirror projection for hemispherical domes

The contents of this web site are © Copyright Paul Bourke or a third party contributer where indicated. You may print or save an electronic copy of parts of this web site for your own personal use. Permission must be sought for any other use.