The routine returns an algebraic representation of the given geometric object.

Users will be asked to provide the names of the axes or the name of the parameter in the parametric equations (when obj is a line) if they are not assigned to names and if the second optional argument is not given.  See xname for an example of this.

The command with(geom3d,Equation) allows the use of the abbreviated form of this command.

$\mathrm{with}\left(\mathrm{geom3d}\right)\:$

$\mathrm{point}\left(A\,0\,0\,0\right),\mathrm{point}\left(B\,1\,2\,3\right)\:$

$\mathrm{line}\left(l\,\left[A\,B\right]\right)$

$l$

$\mathrm{Equation}\left(l\,m\right)$

$\left[m\,2m\,3m\right]$

$\mathrm{point}\left(C\,3\,7\,11\right)\:$

$\mathrm{plane}\left(p\,\left[A\,B\,C\right]\,\left[a\,b\,c\right]\right)\:$

$\mathrm{Equation}\left(p\right)$

$a-2b+c=0$