spring

NAME

spring

SYNOPSIS

      spring j [-s stiff] [-l dist] [-b bend] [-a theta] [-t tether]

DESCRIPTION

spring specifies the default intra-entity elastic link properties. spring has one required argument. The required argument specifies the entity type that is to have the default elastic links set. The possibilities for j are;  

$$\begin{tabular} {\vert c\vert l\vert} \hline argument & ty... ... & singlets \ S & polygon singlets \ \hline \end{tabular}$$ (16)

spring interpretes the following options.

• -s stiff = S_l from (4), link stiffness
• -l dist = R_l from (4), link resting length relative to h
• -b bend = S_b from (5), angle bending stiffness
• -a theta = $\theta$ from (6), resting angle in radians
• -t tether = S_T,p from (7), tether stiffness

To set the elastic link properties of all the entities, the spring commands should be issued either with the A option or with the individual entity types. spring can be used numerous times, however, the previous defaults are overwritten with each new call. Thus with multiple uses, it is wise to set all five options with every call.

If the spring command is omitted, then the program has hard coded defaults (listed in entity definition statements). Additionally, the elastic link properties of each individual entity can be specified using the entity definition statements.

EXAMPLE

          spring p -l 4000.0 -a 8000.0 -h 0.0

This commands sets the link stiffness, bending stiffness and the resting angle of a polgon.