JCSG

Documentation

Javadoc Generated Documentation

Spike Examples Part of BowlerStudio

Build Status

Overview

Java implementation of BSP based CSG (Constructive Solid Geometry). It is the only simple and free Java implementation I am aware of. This implementation uses an optimized CSG algorithm based on csg.js (see CSG and Node classes). Thanks to the author for creating the csg.js library.

In addition to CSG this library provides the following features:

• optimized difference() and union() operations (many thanks to Sebastian Reiter)
• extrusion of concave, non-intersecting polygons (uses Poly2Tri for triangulation)
• convex hull (uses QuickHull3D)
• weighted transformations (Scale, Rotation, Translation and Mirror)
• STL import and export (STLLoader from Fiji)
• OBJ export including material information (see screenshot below)
• supports conversion of CSG's to JavaFX 3D nodes
• 3d text support (using FXyz)

JCSG on stackoverflow.

Maven

<dependency>
  <groupId>com.neuronrobotics</groupId>
  <artifactId>JavaCad</artifactId>
  <version>VERSION_FROM_BADGE</version>
  <type>zip</type>
</dependency>

Gradle

repositories {
	//com.neuronrobotics hosting point
	maven { url 'https://oss.sonatype.org/content/repositories/staging/' }
}
dependencies {
	compile "com.neuronrobotics:JavaCad:VERSION_FROM_BADGE"
}

How to Build JCSG

Requirements

• Java >= 1.8
• Internet connection (dependencies are downloaded automatically)
• IDE: Gradle Plugin (not necessary for command line usage)

IDE

Open the JCSG Gradle project in your favourite IDE (tested with NetBeans 7.4) and build it by calling the assemble task.

Command Line

Navigate to the Gradle project (e.g., path/to/JCSG) and enter the following command

Bash (Linux/OS X/Cygwin/other Unix-like shell)

sudo update-alternatives --config java # select Java 8
sudo apt-get install libopenjfx-java
bash gradlew assemble

Windows (CMD)

gradlew assemble

Code Sample:

// we use cube and sphere as base geometries
CSG cube = new Cube(2).toCSG();
CSG sphere = new Sphere(1.25).toCSG();

// perform union, difference and intersection
CSG cubePlusSphere = cube.union(sphere);
CSG cubeMinusSphere = cube.difference(sphere);
CSG cubeIntersectSphere = cube.intersect(sphere);
        
// translate geometries to prevent overlapping 
CSG union = cube.
        union(sphere.transformed(Transform.unity().translateX(3))).
        union(cubePlusSphere.transformed(Transform.unity().translateX(6))).
        union(cubeMinusSphere.transformed(Transform.unity().translateX(9))).
        union(cubeIntersectSphere.transformed(Transform.unity().translateX(12)));
        
// save union as stl
try {
    FileUtil.write(
            Paths.get("sample.stl"),
            union.toStlString()
    );
} catch (IOException ex) {
    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}

CI Publish HOWTO set up

1. Export your gpg private key from the system that you have created it.

   1. Find your key-id (using gpg --list-secret-keys --keyid-format=long)
   2. Put the GPG id into a variable OSSRH_GPG_SECRET_KEY_ID
   3. Export the gpg secret key to an ASCII file using gpg --export-secret-keys -a <key-id> > secret.txt
   4. Edit secret.txt using a plain text editor, and replace all newlines with a literal "\n" until everything is on a single line

2. Set up GitHub Actions secrets

   1. Create a secret called OSSRH_GPG_SECRET_KEY using the text from your edited secret.txt file (the whole text should be in a single line)
   2. Create a secret called OSSRH_GPG_SECRET_KEY_PASSWORD containing the password for your gpg secret key

3. Add Maven Credentials

   1. In ~/gradle.properties, osshUsername MAVEN_USERNAME
   2. In ~/gradle.properties, osshPassword MAVEN_PASSWORD

4. Create a GitHub Actions step to install the gpg secret key

   1. Add an action similar to:

      - id: install-secret-key
        name: Install gpg secret key
        run: |
          cat <(echo -e "${{ secrets.OSSRH_GPG_SECRET_KEY }}") | gpg --batch --import
          gpg --list-secret-keys --keyid-format LONG

   2. Verify that the secret key is shown in the GitHub Actions logs
   3. You can remove the output from list secret keys if you are confident that this action will work, but it is better to leave it in there