bibliography | introduction | back to homepage | 2D curves | 3D curves | fractals | polyhedra |
SURFACES
See the notations below.
Surfaces starting with
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
ASYMPTOTIC PLANE OF A GENERATRIX OF A RULED SURFACE
ATTRACTION (SURFACE OF EQUAL/)
ATTRACTION (SOLID OF MAXIMAL/)
CENTRAL POINT OF A GENERATRIX OF A RULED SURFACE
CHARACTERISTIC OF A MANIFOLD, OF A SURFACE (EULER/)
CONE OR CONICAL SURFACE
CURVATURE (SURFACE OF REVOLUTION WITH CONSTANT GAUSSIAN/)
CUSPIDAL EDGE OF A DEVELOPABLE RULED SURFACE
CYLINDER
OF REVOLUTION
DARBOUX CYCLIDE
DEVELOPABLE SURFACE (INVOLUTE OF A/)
DYCK'S SURFACE
EDGE
(CUSPIDAL/)
ELASTICITY SURFACE (FRESNEL'S)
ENVELOPE OF A FAMILY OF SURFACES
EULER CHARACTERISTIC
OF A MANIFOLD, OF A SURFACE
FLIPPABLE SURFACE
GYROID
HANDLES (SURFACE WITH n/)
HYPERBOLOID
OF ONE
SHEET (H1)
OF TWO
SHEETS (H2)
HYPERSPHERE (3-DIMENSIONAL/, n DIMENSIONAL/)
HYPERTORURS
INDICATRIX
(DUPIN/)
INVERSE OF A SURFACE WITH RESPECT TO A SPHERE
INVOLUTE OF A DEVELOPABLE SURFACE
ISOMETRIC TO ANOTHER SURFACE (SURFACE/)
LINE
CURVATURE/,
ASYMPTOTIC/,
GEODESIC/
LINE (TOPOGRAPHIC/):
LEVEL/,
SLOPE/,
THALWEG/,
APEX/,
LIOUVILLE SURFACE
MANIFOLD (TOPOLOGICAL/, DIFFERENTIAL/,
ALGEBRAIC/)
MERIDIAN OF A SURFACE OF REVOLUTION
MÖBIUS STRIP, OR BAND, OR RING
MORIN'S SURFACE
NADIRASHVILI
SURFACE
OBLATE (ELLIPSOID OF REVOLUTION/)
OVOID
PAPER LANTERN (SCHWARZ/)
PARABOLIC (POINT / D'UNE SURFACE)
PARALLEL TO ANOTHER SURFACE (SURFACE/)
POLAR DEVELOPABLE OF A SKEW CURVE
POLAR OF A SURFACE, OF A CURVE, WITH RESPECT TO A SPHERE (RECIPROCAL/)
PRESSURE (TOWER WITH CONSTANT/)
PROLATE ELLIPSOID OF REVOLUTION
RIEMANN FINITE MINIMAL SURFACE
SCREW WITH SQUARE THREAD (SURFACE OF THE)
SCREW WITH TRIANGULAR THREAD (SURFACE OF THE/)
SLOPE LINE, OR OF GREATEST SLOPE
STRAIGHT DIRECTRIX (SURFACE WITH A/)
STRICTION LINE OF A NON DEVELOPABLE RULED SURFACE
SUM OF TWO SURFACES (CONNECTED/)
SYMMETRY (SURFACE WITH ROTATIONAL/)
SYSTEM (TRIPLE ORTHOGONAL)
TAKAGI (MOUNT/)
TRICKLE OF WATER (SURFACE OF THE/)
TRIPLE ORTHOGONAL SYSTEM OF SURFACES
TUBE or TUBULAR SURFACE
UMBILIC
(S) surface currently under study.
M: current point of the surface.
(O, ,,) direct orthonormal frame, with axes Ox, Oy and Oz.
(): Cartesian coordinates of M.
(): cylindrical coordinates of M; .
(r, q, l) or (r, q, j): spherical coordinates of M (q is the longitude, l is the latitude and j the colatitude).
Generalization to toroidal coordinates (r,
r,
q,l):
u, v: parameters.
Cartesian equation, parametrization: characterization in terms of x, y et z.
Cylindrical equation, parametrization: characterization in terms of r, q and z.
Spherical equation, parametrization: characterization in terms of r, q and l.
, , ,,.
,, : coefficients of the first fundamental quadratic form (s = curvilinear abscissa of a curve traced on the surface):
.
: Surface element.
: normal vector.
, , :
coefficients of the second fundamental quadratic form:
R1 and R2: principal (i.e. extremal) radii of curvature at M.
and : principal
curvatures at M.
: Gaussian (or total) curvature at M.
: mean curvature at M.
.
Let be (C) a curve drawn on (S) passing through
M
, of Frenet trihedron .
The Darboux-Ribaucour (or geodesic) trihedron
is
where .
,
angle of the rotation passing from Frenet to Darboux, angle between the
osculating plane and the tangent plane to the surface:
.
Frenet formulas : ; Darboux formulas : ,
: normal radius of curvature (radius of curvature of the normal section
of the surface, tangent to the curve),
: normal curvature.
: geodesic
radius of curvature,
: geodesic curvature ; it is the curvature of the two asymptotic
lines passing through M. (So ).
:
geodesic torsion radius ;
: geodesic torsion ; it is the torsion of asymptotic lines, and geodesics
passing through M (as well as pseudo-geodesics).
Let
the angle be between the first principal direction and the tangent to (C);
we have the
Euler formula :
and the Bonnet formula : .
bibliography | introduction | back to homepage | 2D curves | 3D curves | fractals | polyhedra |