# AddCylinder

NAME

    AddCylinder - add cylinder for schematic drawing

SYNOPSIS

    AddCylinder ( least_square | spacing )

DESCRIPTION

Add a cylinder that approximates the selected atoms. The argument selects between two fit criteria. 'least_square' does a least square fit of the cylinder surface to the atoms, 'spacing' takes the axis direction that gives the most regular spacing of atoms. The results are normally very similar, but 'spacing' works better than 'least_square' if very few atoms are given.

A cylinder is added for each molecule that has selected atoms. A minimum number of atoms (5 for least_square, 4 for spacing) must be selected, otherwise the cylinder cannot be determined and an error message is issued.

Cylinders can be used for showing alpha helices in schematic drawings. For good results, it is recommended to either select the CA or all backbone atoms within a helix region.

The created primitives have the property "cylinder".

EXAMPLE

    AddCylinder spacing

SEE ALSO

`SelectAtom`, `StyleCylinder`, `ColorPrim`, `LengthPrim`, `RemovePrim`, `AddRibbon`, `AddSolid`, `AddDipole`

DATE

970930