The goal of each stl_cmd is to provide a simple command line interface for manipulating binary STL files. stl_cmd aims to be easy to set up, and is geared towards teaching basic terminal usage and programming skills in the 3D printing space.
git clone https://github.com/AllwineDesigns/stl_cmd.git cd stl_cmd make make install # will install to /usr/local/bin by default make prefix=/some/other/path install # will install to /some/other/path/bin make DESTDIR=/some/other/path install # will install to /some/other/path/usr/local/bin make DESTDIR=/some/other/path prefix=/usr # will install to /some/other/path/usr/bin
The stl_cmds will be compiled and placed in the bin/ directory in the root of the stl_cmd repo. Add it to your path and you can perform the following commands.
stl_cmd releases are now a part of Debian! You can install them using apt-get.
# on Debian unstable or Ubuntu bionic sudo apt-get install stlcmd
You have an STL file specified in inches and you want to convert it to mm.
stl_transform -s 25.4 my_file_inches.stl my_file_mm.stl
Discard stored normals and calculate them based on vertex ordering (can fix some broken stl files).
stl_normals -c my_file.stl my_fixed_file.stl
Count the number of triangles in an STL file.
Set the header of your STL file to contain copyright information.
stl_header -s "My File. Copyright <Your name> 2014." my_file.stl
The following commands create STL files.
stl_empty <output file>
Outputs an empty binary STL file. Can be useful to initialize an empty STL file when merging several files together.
stl_cube [ -w <width> ] [ <output file> ]
Outputs a binary STL file of a cube with the provided width. If no output file is provided, data is sent to stdout.
stl_sphere [-r <radius> ] [ -s <longitudinal segments> ] [ -t <latitudinal segments> ] [ <output file> ]
Outputs an stl file of a sphere with the provided radius and number of segments. If the radius is omitted, it defaults to 1. If longitudinal segments is omitted, it defaults to 32. If latitudinal segments is omitted, it defaults to half the longitudinal segments. If no output file is provided, data is sent to stdout.
stl_cylinder [-r <radius> ] [-h <height>] [ -s <segments> ] [ <output file> ]
Outputs an stl file of a cylinder with the provided radius, height and number of segments. If the radius or height are omitted, they default to 1. If segments is omitted, it defaults to 32. If no output file is provided, data is sent to stdout.
stl_cone [-r <radius> ] [-t <top radius>] [-h <height>] [ -s <segments> ] [ <output file> ]
Outputs an stl file of a cone with the provided radius, top radius, height and number of segments. If the radius or height are omitted, they default to 1. If top radius is omittted, it defaults to 0. If top radius is greater than 0, it outputs a truncated cone. If segments is omitted, it defaults to 32. If no output file is provided, data is sent to stdout.
stl_torus [-o <outer radius> ] [-i <inner radius>] [ -s <segments> ] [ -c <cross sectional segments> ] [ <output file> ]
Outputs an stl file of a torus with the provided inner radius, outter radius, and number of segments. If the inner radius is omitted, it defaults to .5. If outer radius is omittted, it defaults to 1. If segments is omitted, it defaults to 32. If cross sectional segments is omitted, it defaults to half the segments. If no output file is provided, data is sent to stdout.
stl_threads [ -f ] [ -D <diameter> ] [ -P <pitch> ] [ -a <angle> ] [ -h <height> ] [ -s <segments> ] <output file>
Outputs an stl file with male or female screw threads per the ISO metric screw thread standard.
-f - Outputs female threads (defaults to male). -D <diameter> - Changes to major diameter of the threads. -P <pitch> - Changes the height of a single thread, aka the pitch per the ISO metric standard. -h <height> - Changes the total height of the threads. -a <angle> - Changes the thread angle (degrees). The standard (and default) is 60 degrees. For 3D printing this can cause overhang issues as 60 degrees results in a 30 degree angle with the ground plane. Setting to 90 degrees results in a 45 degree angle with the ground plane. -s <segments> - Changes the resolution of the generated STL file. More segments yields finer resolution. <segments> is the number of segments to approximate a circle. Defaults to 72 (every 5 degrees).
The following commands display information about STL files. In some cases, they make modifications to the STL files related to that information.
stl_header [-s <header>] [-o <output file>] <input file>
Prints or sets the data in the header section of a binary STL file. The header section is rarely used, but can store a small amount of data (80 characters). Copyright info or a very brief description are some possibilities.
stl_count [ <input file> ]
Prints the number of triangles in the provided binary STL file. If no input file is provided, data is read from stdin.
stl_normals [ -v ] [ -c ] [ -r ] [ <input file> ] [ <out file> ]
Compares normals stored in input file with normals calculated from the vertex ordering. Provided flags can tell stl_normals to fix the normals or reverse the point ordering.
stl_bbox <input file>
Prints bounding box information about the provided binary STL file.
stl_convex [ -v ] <input file>
Determines whether an STL file is a convex polyheda by calculating Euler's characteristic. Prints convex if the STL file is convex, or not convex otherwise. If the -v flag is used a verbose message is printed that shows the calculation.
stl_borders <input file>
Outputs the number of border edges in the STL files. This should be 0 for manifold meshes. If the output is greater than 0, the mesh has holes in it or has non-manifold edges.
stl_spreadsheet <input file>
Outputs normal and position data for every triangle (normal, point1, point2 and point3 specified per row) in a tab delimited format that can be opened as a spreadsheet.
These commands modify existing STL files.
stl_merge [ -o <output file> ] [ <input file> ... ]
Combines binary STL files into a single one. If no output file is provided, data is written to stdout.
stl_transform [[ <transformation> ] ...] <input file> <output file>
Performs any number of transformations in the order listed on the command line. Transformations include:
-rx <angle> - rotates <angle> degrees about the x-axis -ry <angle> - rotates <angle> degrees about the y-axis -rz <angle> - rotates <angle> degrees about the z-axis -s <s> - uniformly scales x, y and z by <s> (cannot be 0) -sx <x> - scales by <x> in x (cannot be 0) -sy <y> - scales by <y> in y (cannot be 0) -sz <z> - scales by <z> in z (cannot be 0) -tx <x> - translates <x> units in x -ty <y> - translates <y> units in y -tz <z> - translates <z> units in z
stl_boolean -a <STL file A> -b <STL file B> [ -i ] [ -u ] [ -d ] <out file>
Performs a CSG boolean operation on STL files A and B using BSP trees. -i will perform the intersection of A and B. -u will perform the union of A and B. -d will perform the difference of A and B.
These are ideas for future commands that may make it into the stl_cmd suite.
Compute the convex hull of the input STL files.
Calculate the surface area of STL files (could be used for price or print time approximations)
Calculate the volume of STL files (could used for price or print time approximations)
Layout a number of stl files on the Z = 0 plane, possibly even attempting to find the flattest side to place each file on.
stl_zero or stl_center
Centers the STL file, with options to put the bottom of the model on the Z = 0 plane.
Extrude a circle or sweep a sphere along a piecewise linear curve.
Extrude a circle or sweep a sphere along a Bezier curve (would probably approximate the Bezier with some number of linear segments and use the same algorithm as stl_segments).
Simplify an STL file while preserving its shape.
Deform an STL file by twisting it.
Deform an STL file by bending it.
Deform an STL file by displacing vertices using noise.
The goal of this project is to be a resource for teaching terminal usage and some basic programming concepts in the 3D printing space. Imagine an assignment which involves building a brick wall. Students would need to use a combination of stl_cube, stl_transform and stl_merge. The commands could be combined in a bash or <insert favorite scripting language> script with for and while loops, could accept input and use conditionals to affect the attributes of the wall.
The terminal is an important tool to learn when programming, but can be boring to learn when just making text based programs. stl_cmd aims to make the intro level terminal usage and programming more interesting by creating 3D printable models. As more commands are added more creative assignments are possible. I hope to grow the suite of commands included in stl_cmd with that goal in mind.
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