Length Units

Length units and conversions. More...

Collaboration diagram for Length Units:

Files
file	length.scad
	Length units and conversions.

Functions
function	length_unit_name (u=length_unit_default, d=1, w=false)
	Return the name for a length unit identifier with dimension. More...
function	length (v, from=length_unit_default, to=length_unit_base, d=1)
	Convert a value from from one units to another with dimensions. More...
function	length_inv (v, from=length_unit_base, to=length_unit_default, d=1)
	Convert a value from from one units to another with dimensions. More...

Variables
	length_unit_base = "mm"
	<string> The base units for value storage.
	length_unit_default = "mm"
	<string> The default units when unspecified.

Shorts
function	l_mm (v)
	Shorthand length conversion for millimeters. More...
function	l_in (v)
	Shorthand length conversion for inches. More...

Detailed Description

Length units and conversions.

Requires:
include <omdl-base.scad>;

These functions allow for lengths to be specified with units. Lengths specified with units are independent of (length_unit_base). There are also unit conversion functions for converting from one unit to another.

The table below enumerates the supported units.

units id	description
pm	picometer
nm	nanometer
um	micrometer
mm	millimeter
cm	centimeter
dm	decimeter
m	meter
km	kilometer
thou, mil	thousandth of an inch
in	inch
ft	feet
yd	yard
mi	mile

Length base units example script

    include <omdl-base.scad>;
 
    length_unit_base = "mm";
    length_unit_default = "in";
 
    // get unit names
    bu = length_unit_name(length_unit_base);
    du = length_unit_name();
 
    // absolute length measurements in base unit.
    c1 = length(1/8);
    c2 = length(3.175, "mm");
    c3 = length(25, "mil");
    c4 = length(1, "ft", d=3);
 
    // convert between units.
    c5 = length(10, from="mil", to="in");
    c6 = length(10, from="ft", to="mm");
 
    // end_include

length_unit_base=mm script output

ECHO: bu = "millimeter"
ECHO: du = "inch"
ECHO: 
ECHO: c1 = 3.175
ECHO: c2 = 3.175
ECHO: c3 = 0.635
ECHO: c4 = 2.83168e+7
ECHO: c5 = 0.01
ECHO: c6 = 3048

length_unit_base=cm script output

ECHO: bu = "centimeter"
ECHO: du = "inch"
ECHO: 
ECHO: c1 = 0.3175
ECHO: c2 = 0.3175
ECHO: c3 = 0.0635
ECHO: c4 = 28316.8
ECHO: c5 = 0.01
ECHO: c6 = 3048

length_unit_base=mil script output

ECHO: bu = "thousandth"
ECHO: du = "inch"
ECHO: 
ECHO: c1 = 125
ECHO: c2 = 125
ECHO: c3 = 25
ECHO: c4 = 1.728e+12
ECHO: c5 = 0.01
ECHO: c6 = 3048

length_unit_base=in script output

ECHO: bu = "inch"
ECHO: du = "inch"
ECHO: 
ECHO: c1 = 0.125
ECHO: c2 = 0.125
ECHO: c3 = 0.025
ECHO: c4 = 1728
ECHO: c5 = 0.01
ECHO: c6 = 3048

Equivalent lengths diagram

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Function Documentation

l_in()

function l_in

(

v

)

Shorthand length conversion for inches.

Parameters

v	<decimal> The value to convert.

Returns

<decimal> The conversion result.

l_mm()

function l_mm

(

v

)

Shorthand length conversion for millimeters.

Parameters

v	<decimal> The value to convert.

Returns

<decimal> The conversion result.

length()

function length	(	v	,
		from	= length_unit_default,
		to	= length_unit_base,
		d	= 1
	)

Convert a value from from one units to another with dimensions.

Parameters

v	<decimal> The value to convert.
from	<string> The units of the value to be converted.
to	<string> The units to which the value should be converted.
d	<integer> The unit dimension. One of [1|2|3].

Returns

<decimal> The conversion result. Returns undef for identifiers or dimensions that are not defined.

Here is the caller graph for this function:

length_inv()

function length_inv	(	v	,
		from	= length_unit_base,
		to	= length_unit_default,
		d	= 1
	)

Convert a value from from one units to another with dimensions.

Parameters

v	<decimal> The value to convert.
from	<string> The units of the value to be converted.
to	<string> The units to which the value should be converted.
d	<integer> The unit dimension. One of [1|2|3].

Returns

<decimal> The conversion result. Returns undef for identifiers or dimensions that are not defined.

length_unit_name()

function length_unit_name	(	u	= length_unit_default,
		d	= 1,
		w	= false
	)

Return the name for a length unit identifier with dimension.

Parameters

u	<string> A length unit identifier.
d	<integer> The unit dimension. One of [1|2|3].
w	<boolean> true for word and false for symbol format.

Returns

<string> The long name for a length unit identifier with dimension. Returns undef for identifiers or dimensions that are not defined.