---
name: "genrev"
section: "1"
platform: "linux"
package: "radiance"
version: "4R1+20120125-1+b1"
release: "Debian 7 (Wheezy)"
platforms: ["linux"]
url: "https://new.carta.tech/genrev"
---

# genrev(1)

generate a RADIANCE description of surface of revolution

## NAME

genrev - generate a RADIANCE description of surface of revolution

## SYNOPSIS

**genrev mat name 'z(t)' 'r(t)' nseg** \[ **-e expr** \]\[ **-f file** \]\[ **-s** \]

## DESCRIPTION

*Genrev* produces a RADIANCE scene description of a surface of revolution. The object will be composed of *nseg* cones, cups, cylinders, tubes or rings following the parametric curve defined by *z(t)* (height) and *r(t)* (radius). When *z* is increasing with t, the surface normal points outward. When *z* is decreasing, the normal points inward. The variable *t* used in the function expressions varies from 0 to 1 in even steps of *1/nseg.* The expressions are of the same type used in RADIANCE function files. Auxiliary expressions and/or files may be specified in any number of *-e* and *-f* options. The *-s* option smooths the surfaces using Phong normal interpolation.

## EXAMPLE

To generate a torus with an inner radius of 1 and an outer radius of 3:

-

  genrev steel torus 'sin(2\*PI\*t)' '2+cos(2\*PI\*t)' 32

## AUTHOR

Greg Ward

## BUGS

The -s option doesn't modify the surface normal correctly for the opposite side.

## SEE ALSO

[genrbox(1)](/genrbox/1.md), [gensurf(1)](/gensurf/1.md), [genworm(1)](/genworm/1.md), [icalc(1)](/icalc/1.md), [rpict(1)](/rpict/1.md), [rvu(1)](/rvu/1.md), [xform(1)](/xform/1.md)