GuruBlog

the Toxiclibs are a very interesting collection of processing libraries. One of the libraries is called volumeutils and allows to use a volumetric space to model a 3D object.

I used it to generate a tentacle and export it as a stl file to make it printable on my 3D-printer.

click here to see it live or download the source-code

In the setup method i define a volumetric space containing 100x100x100 voxel, a iso surface and a Triangle mesh (which is needed to display the object and export it later)

gfx = new ToxiclibsSupport(this);
VolumetricSpace volume = new VolumetricSpaceArray( new Vec3D(100,200,100), 100, 100, 100 );
IsoSurface surface = new ArrayIsoSurface( volume );
mesh = new TriangleMesh();

Then i define a volumentric brush - in this case a sphere and use it to draw a spiral while increasing the raduis of the brush-sphere.

VolumetricBrush brush = new RoundBrush( volume, 10 );
for ( int i=0; i < 20; i ++) {
  brush.setSize( i*1.2 + 6 );
  float x = cos( i * TWO_PI / 20 ) * 10;
  float y = sin( i * TWO_PI / 20 ) * 10;
  brush.drawAtAbsolutePos( new Vec3D(x,-25+i * 7,y), 1 );
}

Then i use the brush to draw the suckers. First I draw a sphere a little bit outside the tentacle and then I draw a second sphere with a smaller raduis and a negative density to remove a section of a sphere and leave a dent.

for ( int i=4; i < 20; i+=4) {
  brush.setSize( i/1.5+4 );

  float x = cos( i * TWO_PI / 20 ) * (i*1.2+16);
  float y = sin( i * TWO_PI / 20 ) * (i*1.2+16);

  brush.drawAtAbsolutePos( new Vec3D(x,-25+i * 7,y), 1 );

 brush.setSize( i/2+2 );
  float x2 = cos( i * TWO_PI / 20  ) * (i*1.2+18);
  float y2 = sin( i * TWO_PI / 20  ) * (i*1.2+18);
  brush.drawAtAbsolutePos( new Vec3D(x2,-25+i * 7,y2), -1.4 );
}

finally the mesh gets generated from the volumetric object.

volume.closeSides();
surface.reset();
surface.computeSurfaceMesh( mesh, .5 );

to display the mesh i use the ToxiclibsSupport to generate the vertices in the draw method

beginShape(TRIANGLES);
gfx.mesh( mesh );
endShape();

exporting the mesh to stl is simply a matter of calling

mesh.saveAsSTL( sketchPath( "tentacle.stl" ));