Right conoid

Image:Right concoid.svg|right|thumb|240px|A right conoid as a ruled surface.
In geometry, a right conoid is a ruled surface generated by a family of straight lines that all intersect perpendicularly to a fixed straight line, called the axis of the right conoid.
Using a Cartesian coordinate system in three-dimensional space, if we take the to be the axis of a right conoid, then the right conoid can be represented by the parametric equations:
where is some function for representing the height of the moving line.

Examples

[Image:Conoid.gif|right|thumb|300px|Generation of a typical right conoid]
A typical example of right conoids is given by the parametric equations
The image on the right shows how the coplanar lines generate the right conoid.
Other right conoids include:

Helicoid:
Whitney umbrella:
Wallis's conical edge:
Plücker's conoid:
hyperbolic paraboloid: .