stl_module – stl-fortran

STL (STereoLithography) file library.

Author

Jacob Williams, Jan 12, 2020.

License

BSD-3

Reference

https://en.wikipedia.org/wiki/STL_(file_format)

Uses

- iso_fortran_env
- iso_c_binding
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Graph Key

Nodes of different colours represent the following:

Solid arrows point from a submodule to the (sub)module which it is descended from. Dashed arrows point from a module or program unit to modules which it uses.

Variables

Type	Visibility	Attributes		Name		Initial
real(kind=wp),	private,	parameter	::	zero	=	0.0_wp
real(kind=wp),	private,	parameter	::	one	=	1.0_wp
real(kind=wp),	private,	parameter	::	deg2rad	=	acos(-1.0_wp)/180.0_wp	degrees to radians
real(kind=wp),	private,	parameter, dimension(3)	::	x_unit	=	[one, zero, zero]	x-axis unit vector
real(kind=wp),	private,	parameter, dimension(3)	::	y_unit	=	[zero, one, zero]	y-axis unit vector
real(kind=wp),	private,	parameter, dimension(3)	::	z_unit	=	[zero, zero, one]	z-axis unit vector

Derived Types

type, private :: plate

a 3D triangular plate. [note that the order of the vertices defines the surface normal via the right-hand rule]

Components

Type	Visibility	Attributes		Name		Initial
real(kind=wp),	public,	dimension(3)	::	v1	=	zero	first vertex
real(kind=wp),	public,	dimension(3)	::	v2	=	zero	second vertex
real(kind=wp),	public,	dimension(3)	::	v3	=	zero	third vertex

type, public :: stl_file

the main class for STL file I/O.

Components

Type	Visibility	Attributes		Name		Initial
integer,	private		::	n_plates	=	0	number of plates
integer,	private		::	chunk_size	=	1000	expand `plates` array in chunks of this size
type(plate),	private,	dimension(:), allocatable	::	plates			the array of plates

Type-Bound Procedures

procedure, public :: write_ascii_stl_file
procedure, public :: write_binary_stl_file
procedure, public :: read => read_binary_stl_file
procedure, public :: read_tab_file
procedure, public :: destroy => destroy_stl_file
procedure, public :: add_plate
procedure, public :: add_sphere
procedure, public :: add_cylinder
procedure, public :: add_curve
procedure, public :: add_cone
procedure, public :: add_arrow
procedure, public :: add_axes
procedure, public :: shift_mesh
procedure, public :: set_chunk_size
procedure, private :: generate_circle
procedure, private :: compute_vertex_scale

Functions

private pure function compute_vertex_scale(me, bounding_box) result(scale)

Compute the scale factor for the vertices (for writing to a file).

Arguments

Type	Intent	Optional	Attributes		Name
class(stl_file),	intent(in)			::	me
real(kind=wp),	intent(in),	optional		::	bounding_box	scale vertices so that model fits in a box of this size (if <=0, no scaling is done)

Return Value real(kind=wp)

scale factor

private pure function perpendicular(v1, v2) result(is_parallel)

Returns true if the two vectors are perpendicular.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=wp),	intent(in),		dimension(:)	::	v1
real(kind=wp),	intent(in),		dimension(:)	::	v2

Return Value logical

private pure function normal(v1, v2, v3) result(n)

Normal vector for the plate (computed using right hand rule).

Arguments

Type	Intent	Attributes		Name
real(kind=wp),	intent(in),	dimension(3)	::	v1	first vertex of the triangle [x,y,z]
real(kind=wp),	intent(in),	dimension(3)	::	v2	second vertex of the triangle [x,y,z]
real(kind=wp),	intent(in),	dimension(3)	::	v3	third vertex of the triangle [x,y,z]

Return Value real(kind=wp), dimension(3)

surface normal vector

private pure function unit(r) result(rhat)

3x1 Unit vector.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=wp),	intent(in),		dimension(3)	::	r

Return Value real(kind=wp), dimension(3)

private pure function cross(a, b) result(axb)

Vector cross product.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=wp),	intent(in),		dimension(3)	::	a
real(kind=wp),	intent(in),		dimension(3)	::	b

Return Value real(kind=wp), dimension(3)

private pure function spherical_to_cartesian(r, alpha, beta) result(rvec)

Convert spherical (r,alpha,beta) to Cartesian (x,y,z).

Arguments

Type	Intent		Name
real(kind=wp),	intent(in)	::	r	magnitude
real(kind=wp),	intent(in)	::	alpha	right ascension [deg]
real(kind=wp),	intent(in)	::	beta	declination [deg]

Return Value real(kind=wp), dimension(3)

[x,y,z] vector

private pure function axis_angle_rotation(v, k, theta) result(vrot)

Author: Jacob Williams
Date: 7/20/2014

Rotate a 3x1 vector in space, given an axis and angle of rotation.

Arguments

Type	Intent	Attributes		Name
real(kind=wp),	intent(in),	dimension(3)	::	v	vector to rotate
real(kind=wp),	intent(in),	dimension(3)	::	k	rotation axis
real(kind=wp),	intent(in)		::	theta	rotation angle [deg]

Return Value real(kind=wp), dimension(3)

result

private pure function vector_projection(a, b) result(c)

The projection of one vector onto another vector.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=wp),	intent(in),		dimension(:)	::	a	the original vector
real(kind=wp),	intent(in),		dimension(size(a))	::	b	the vector to project on to

Return Value real(kind=wp), dimension(size(a))

the projection of a onto b

private pure function vector_projection_on_plane(a, b) result(c)

Project a vector onto a plane.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=wp),	intent(in),		dimension(3)	::	a	the original vector
real(kind=wp),	intent(in),		dimension(3)	::	b	the plane to project on to (a normal vector)

Return Value real(kind=wp), dimension(3)

the projection of a onto the b plane

Subroutines

private subroutine destroy_stl_file(me)

Destroy an stl_file.

Arguments

Type	Intent	Optional	Attributes		Name
class(stl_file),	intent(inout)			::	me

private subroutine set_chunk_size(me, chunk_size)

Set the chunk size in the class.

Arguments

Type	Intent	Optional	Attributes		Name
class(stl_file),	intent(inout)			::	me
integer,	intent(in)			::	chunk_size	must be >0

private subroutine add_plate(me, v1, v2, v3)

Add a plate to the class.

Arguments

Type	Intent	Attributes		Name
class(stl_file),	intent(inout)		::	me
real(kind=wp),	intent(in),	dimension(3)	::	v1	first vertex
real(kind=wp),	intent(in),	dimension(3)	::	v2	second vertex
real(kind=wp),	intent(in),	dimension(3)	::	v3	third vertex

private subroutine write_binary_stl_file(me, filename, istat, bounding_box)

Generate a binary STL file.

Arguments

Type	Intent	Optional		Name
class(stl_file),	intent(in)		::	me
character(len=*),	intent(in)		::	filename	STL file name
integer,	intent(out)		::	istat	`iostat` code (=0 if no errors)
real(kind=wp),	intent(in),	optional	::	bounding_box	scale vertices so that model fits in a box of this size (if <=0, no scaling is done)

private subroutine read_binary_stl_file(me, filename, istat)

Read a binary STL file.

Arguments

Type	Intent		Name
class(stl_file),	intent(out)	::	me
character(len=*),	intent(in)	::	filename	STL file name
integer,	intent(out)	::	istat	`iostat` code (=0 if no errors)

private subroutine read_tab_file(me, filename, istat)

Read a text vertex-facet file.

Arguments

Type	Intent		Name
class(stl_file),	intent(out)	::	me
character(len=*),	intent(in)	::	filename	Vertex-facet file name
integer,	intent(out)	::	istat	`iostat` code (=0 if no errors)

private subroutine write_ascii_stl_file(me, filename, modelname, istat, bounding_box)

Generate an ascii STL file.

Arguments

Type	Intent	Optional		Name
class(stl_file),	intent(in)		::	me
character(len=*),	intent(in)		::	filename	STL file name
character(len=*),	intent(in)		::	modelname	the solid name (should not contain spaces)
integer,	intent(out)		::	istat	`iostat` code (=0 if no errors)
real(kind=wp),	intent(in),	optional	::	bounding_box	scale vertices so that model fits in a box of this size (if <=0, no scaling is done)

private subroutine shift_mesh(me)

Shift the vertex coordinates so that there are no non-positive components.

Arguments

Type	Intent	Optional	Attributes		Name
class(stl_file),	intent(inout)			::	me

private subroutine add_sphere(me, center, radius, num_lat_points, num_lon_points)

Add a sphere to an STL file.

Arguments

Type	Intent	Attributes		Name
class(stl_file),	intent(inout)		::	me
real(kind=wp),	intent(in),	dimension(3)	::	center	coordinates of sphere center [x,y,z]
real(kind=wp),	intent(in)		::	radius	radius of the sphere
integer,	intent(in)		::	num_lat_points	number of latitude points (not counting poles)
integer,	intent(in)		::	num_lon_points	number of longitude points

private subroutine add_cylinder(me, v1, v2, radius, num_points, initial_cap, final_cap, initial_normal, final_normal, final_normal_used, initial_vector, final_initial_vector_used)

Add a cylinder to an STL file.

Arguments

Type	Intent	Optional	Attributes		Name
class(stl_file),	intent(inout)			::	me
real(kind=wp),	intent(in),		dimension(3)	::	v1	coordinates of initial point
real(kind=wp),	intent(in),		dimension(3)	::	v2	coordinates of final point
real(kind=wp),	intent(in)			::	radius	radius of the cylinder
integer,	intent(in)			::	num_points	number of point on the circle (>=3)
logical,	intent(in)			::	initial_cap	add a cap plate to the initial point
logical,	intent(in)			::	final_cap	add a cap plate to the final point
real(kind=wp),	intent(in),	optional,	dimension(3)	::	initial_normal	outward normal vector for initial circle
real(kind=wp),	intent(in),	optional,	dimension(3)	::	final_normal	outward normal vector for final circle
real(kind=wp),	intent(out),	optional,	dimension(3)	::	final_normal_used	outward normal vector for final circle actually used
real(kind=wp),	intent(in),	optional,	dimension(3)	::	initial_vector	vector to use to generate the initial circle (x_unit by default)
real(kind=wp),	intent(out),	optional,	dimension(3)	::	final_initial_vector_used	the initial vector used for the final cap to generate the points

private subroutine add_cone(me, v1, v2, radius, num_points, initial_cap, initial_normal)

Add a cone to an STL file.

Arguments

Type	Intent	Optional	Attributes		Name
class(stl_file),	intent(inout)			::	me
real(kind=wp),	intent(in),		dimension(3)	::	v1	coordinates of initial point (bottom of the cone)
real(kind=wp),	intent(in),		dimension(3)	::	v2	coordinates of final point (point of the cone)
real(kind=wp),	intent(in)			::	radius	radius of the cone (the bottom plate)
integer,	intent(in)			::	num_points	number of point on the circle (>=3)
logical,	intent(in)			::	initial_cap	add a cap plate to the initial point (bottom)
real(kind=wp),	intent(in),	optional,	dimension(3)	::	initial_normal	outward normal vector for initial plate (bottom)

private subroutine add_axes(me, origin, vx, vy, vz, radius, num_points, arrowhead_radius_factor, arrowhead_length_factor)

Add x,y,z axes to an STL file.

Arguments

Type	Intent	Attributes		Name
class(stl_file),	intent(inout)		::	me
real(kind=wp),	intent(in),	dimension(3)	::	origin	coordinates of the origin of the axes
real(kind=wp),	intent(in),	dimension(3)	::	vx	x axis vector
real(kind=wp),	intent(in),	dimension(3)	::	vy	y axis vector
real(kind=wp),	intent(in),	dimension(3)	::	vz	z axis vector
real(kind=wp),	intent(in)		::	radius	radius of the cylinder
integer,	intent(in)		::	num_points	number of point on the circle (>=3)
real(kind=wp),	intent(in)		::	arrowhead_radius_factor	arrowhead cone radius factor (multiple of cylinder radius)
real(kind=wp),	intent(in)		::	arrowhead_length_factor	arrowhead tip length factor (multiple of vector length)

private subroutine add_arrow(me, origin, v, radius, num_points, arrowhead_radius_factor, arrowhead_length_factor)

Add an arrow to an STL file.

Arguments

Type	Intent	Attributes		Name
class(stl_file),	intent(inout)		::	me
real(kind=wp),	intent(in),	dimension(3)	::	origin	coordinates of the origin of the axes
real(kind=wp),	intent(in),	dimension(3)	::	v	vector
real(kind=wp),	intent(in)		::	radius	radius of the cylinder
integer,	intent(in)		::	num_points	number of point on the circle (>=3)
real(kind=wp),	intent(in)		::	arrowhead_radius_factor	arrowhead cone radius factor (multiple of cylinder radius)
real(kind=wp),	intent(in)		::	arrowhead_length_factor	arrowhead tip length factor (multiple of vector length)

private subroutine generate_circle(me, c, radius, n, nc, add_circle, circle, initial_vector, cw)

Generate the points in a circle, and optionally add it as a plate.

Arguments

Type	Intent	Optional	Attributes		Name
class(stl_file),	intent(inout)			::	me
real(kind=wp),	intent(in),		dimension(3)	::	c	center of the circle
real(kind=wp),	intent(in)			::	radius	radius of the cylinder
real(kind=wp),	intent(in),		dimension(3)	::	n	normal vector to the circle
integer,	intent(in)			::	nc	number of points on the circle (must be at least 3)
logical,	intent(in)			::	add_circle	to also add to the circle as a plate
real(kind=wp),	intent(out),		dimension(:,:), allocatable	::	circle	points on the circle
real(kind=wp),	intent(in),	optional,	dimension(3)	::	initial_vector	vector to use to generate the initial circle (x_unit by default)
logical,	intent(in),	optional		::	cw	generate the points in the clockwise direction abound n (default is false)

private subroutine add_curve(me, x, y, z, radius, num_points, initial_cap, initial_normal, final_cap, final_normal, initial_vector)

Add a curve to an STL file.

Arguments

Type	Intent	Optional	Attributes		Name
class(stl_file),	intent(inout)			::	me
real(kind=wp),	intent(in),		dimension(:)	::	x	x coordinate array
real(kind=wp),	intent(in),		dimension(:)	::	y	y coordinate array
real(kind=wp),	intent(in),		dimension(:)	::	z	z coordinate array
real(kind=wp),	intent(in)			::	radius	radius of the cylinder
integer,	intent(in)			::	num_points	number of point on the cylinder perimeter
logical,	intent(in),	optional		::	initial_cap	add a cap plate to the initial point
real(kind=wp),	intent(in),	optional,	dimension(3)	::	initial_normal	outward normal vector for initial circle
logical,	intent(in),	optional		::	final_cap	add a cap plate to the final point
real(kind=wp),	intent(in),	optional,	dimension(3)	::	final_normal	outward normal vector for final circle
real(kind=wp),	intent(in),	optional,	dimension(3)	::	initial_vector	vector to use to generate the first circle (x_unit by default)

stl_module Module

Contents

Variables

Derived Types

Functions

Subroutines

Author

License

Reference

Uses

Variables

Derived Types

type, private :: plate

Components

type, public :: stl_file

Components

Type-Bound Procedures

Functions

private pure function compute_vertex_scale(me, bounding_box) result(scale)

Arguments

Return Value real(kind=wp)

private pure function perpendicular(v1, v2) result(is_parallel)

Arguments

Return Value logical

private pure function normal(v1, v2, v3) result(n)

Arguments

Return Value real(kind=wp), dimension(3)

private pure function unit(r) result(rhat)

Arguments

Return Value real(kind=wp), dimension(3)

private pure function cross(a, b) result(axb)

Arguments

Return Value real(kind=wp), dimension(3)

private pure function spherical_to_cartesian(r, alpha, beta) result(rvec)

Arguments

Return Value real(kind=wp), dimension(3)

private pure function axis_angle_rotation(v, k, theta) result(vrot)

Arguments

Return Value real(kind=wp), dimension(3)

private pure function vector_projection(a, b) result(c)

Arguments

Return Value real(kind=wp), dimension(size(a))

private pure function vector_projection_on_plane(a, b) result(c)

Arguments

Return Value real(kind=wp), dimension(3)

Subroutines

private subroutine destroy_stl_file(me)

Arguments

private subroutine set_chunk_size(me, chunk_size)

Arguments

private subroutine add_plate(me, v1, v2, v3)

Arguments

private subroutine write_binary_stl_file(me, filename, istat, bounding_box)

Arguments

private subroutine read_binary_stl_file(me, filename, istat)

Arguments

private subroutine read_tab_file(me, filename, istat)

Arguments

private subroutine write_ascii_stl_file(me, filename, modelname, istat, bounding_box)

Arguments

private subroutine shift_mesh(me)

Arguments

private subroutine add_sphere(me, center, radius, num_lat_points, num_lon_points)

Arguments

private subroutine add_cylinder(me, v1, v2, radius, num_points, initial_cap, final_cap, initial_normal, final_normal, final_normal_used, initial_vector, final_initial_vector_used)

Arguments

private subroutine add_cone(me, v1, v2, radius, num_points, initial_cap, initial_normal)

Arguments

private subroutine add_axes(me, origin, vx, vy, vz, radius, num_points, arrowhead_radius_factor, arrowhead_length_factor)

Arguments

private subroutine add_arrow(me, origin, v, radius, num_points, arrowhead_radius_factor, arrowhead_length_factor)

Arguments

private subroutine generate_circle(me, c, radius, n, nc, add_circle, circle, initial_vector, cw)

Arguments

private subroutine add_curve(me, x, y, z, radius, num_points, initial_cap, initial_normal, final_cap, final_normal, initial_vector)

Arguments