COIL(1)

NAME

coil - generate a coil as a BRL-CAD pipe primitive

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SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO
AUTHOR
COPYRIGHT
BUG REPORTS

SYNOPSIS

coil [-d mean_outer_diameter] [-w wire_diameter] [-H helix_angle] [-p pitch]
     [-n number_of_turns] [-s start_cap_type] [-e end_cap_type]
     [-S number_of_turns,mean_outer_diameter,wire_diameter,helix_angle,pitch,winding_direction]
     [-l overall_length] [-L] [name]

coil generates a coil modeled as a BRL-CAD pipe primitive from a set of dimensional parameters. If no parameters are supplied, a default coil is created. All lengths are in millimeters and the helix angle is in degrees.

When run as a standalone program, the coil is written to a new database named coil.g; coil refuses to overwrite an existing file of that name. When run as a command inside a modeling environment such as mged(1) or archer(1), the coil is created in the currently open database.

The created object is named coil by default; an alternate name may be given as a trailing argument. The result is a combination unioning the coil core pipe (and, for ground caps, subtracting the capping solids).

OPTIONS

-d mean_outer_diameter: Mean outer diameter of the coil in millimeters.
-w wire_diameter: Diameter of the wire wound into the coil in millimeters.
-H helix_angle: Helix angle of the coil in degrees.
-p pitch: Distance, in millimeters, between the center of the wire at the beginning and end of a single turn. The minimum (and default) value is the wire diameter; a smaller pitch is clamped up to the wire diameter.
-n number_of_turns: Number of turns in the coil. Must be a positive integer; fractional turns are not supported.
-s start_cap_type: Capping style for the start of the coil. 0 (default) applies no special styling, 1 is a squared-off cap, 2 grinds the cap flat in the plane normal to the coiling direction, and 3 both squares off and grinds the cap. Any non-default cap adds extra turns beyond those requested with -n.
-e end_cap_type: Capping style for the end of the coil. Values are the same as for -s.
-S number_of_turns,mean_outer_diameter,wire_diameter,helix_angle,pitch,winding_direction: Define one coil section as a comma-delimited list of all six values (winding_direction is 1 for right-handed, anything else for left-handed). Repeat -S to build a multi-section coil; sections are stacked from the origin in the order given. Specifying any -S section causes all other dimensional options to be ignored (capping with -s/-e still applies).
-l overall_length: Clamp the overall length of the coil to the given value in millimeters. Only effective for uncapped coils with a zero helix angle. To fit the length, pitch is adjusted first, then turns are removed, and finally wire diameter is reduced. Length clamping does not apply to -S sections.
-L: Create a left-handed coil. The default is right-handed (winding proceeds in +x from the start); -L winds in -x.
-h, -?: Print usage information and exit.

EXAMPLES

Example 1. Create a named spring with specific dimensions

coil -d 20 -w 2 -p 5 -n 10 my_spring

Writes coil.g containing a 10-turn coil named my_spring with a 20 mm mean outer diameter, 2 mm wire, and 5 mm pitch.

Example 2. Create a coil with ground ends and inspect its volume

coil -d 50 -w 5 -n 12 -s 3 -e 3 valve_spring
mged -c coil.g 'analyze valve_spring'

Builds a compression-spring-style coil whose ends are squared off and ground flat, then opens the database in mged(1) to report the part’s bounding box and volume.

Example 3. Build a two-section coil

coil -S 10,1000,50,60,800,1 -S 10,1000,50,0,100,1 stacked_coil

Stacks a 10-turn section with a 60-degree helix angle and 800 mm pitch on top of a tighter 10-turn section, both right-handed, in a single stacked_coil object.