I had some issues with Processing 2.0 and DXF a couple of years ago and whipped out a basic DXF writing function. Here's the same approach used on the code you linked to:
import ddf.minim.analysis.*;
import ddf.minim.*;
//audio
Minim minim;
AudioInput microphone;
FFT fftLog;
//audio-driven mesh
Waveform audio3D;
//DXF output
boolean record;
PrintWriter out;
void setup()
{
size(1250,750,P3D); //screen proportions
noStroke();
minim = new Minim(this);
microphone = minim.getLineIn(Minim.STEREO, 4096);
background(255);
fftLog = new FFT(microphone.bufferSize(),microphone.sampleRate());
fftLog.logAverages(1,2); //adjust numbers to adjust spacing;
float w = float (width/fftLog.avgSize());
float x = w;
float y = 0;
float z = 50;
float radius = 10;
audio3D = new Waveform(x,y,z,radius);
}
void draw()
{
background(0);
directionalLight(126,126,126,sin(radians(frameCount)),cos(radians(frameCount)),1);
ambientLight(102,102,102);
if (frameCount>200)
{
for(int i = 0; i < fftLog.avgSize(); i++){
float zoom = 1;
float jitter = (fftLog.getAvg(i)*2);
//println(jitter);
PVector foc = new PVector(audio3D.x+jitter, audio3D.y+jitter, 0);
PVector cam = new PVector(zoom, zoom, -zoom);
camera(foc.x+cam.x+50,foc.y+cam.y+50,foc.z+cam.z,foc.x,foc.y,foc.z,0,0,1);
}
}
//update FFT
fftLog.forward(microphone.mix);
//update 3D mesh
audio3D.update();
audio3D.textdraw();
audio3D.plotTrace();
}
void stop(){
microphone.close();
minim.stop();
super.stop();
}
class Waveform
{
float x,y,z;
float radius;
PVector[] pts = new PVector[fftLog.avgSize()];
PVector[] trace = new PVector[0];
Waveform(float incomingX, float incomingY, float incomingZ, float incomingRadius)
{
x = incomingX;
y = incomingY;
z = incomingZ;
radius = incomingRadius;
}
void update()
{
plot();
}
void plot()
{
for(int i = 0; i < fftLog.avgSize(); i++)
{
int w = int(width/fftLog.avgSize());
x = i*w;
y = frameCount*5;
z = height/4-fftLog.getAvg(i)*4; //change multiplier to reduces height default '10'
stroke(0);
point(x, y, z);
pts[i] = new PVector(x, y, z);
//increase size of array trace by length+1
trace = (PVector[]) expand(trace, trace.length+1);
//always get the next to last
trace[trace.length-1] = new PVector(pts[i].x, pts[i].y, pts[i].z);
}
}
void textdraw()
{
for(int i =0; i<fftLog.avgSize(); i++){
pushMatrix();
translate(pts[i].x, pts[i].y, pts[i].z);
rotateY(PI/2);
rotateZ(PI/2);
fill(255,200);
text(round(fftLog.getAvg(i)*100),0,0,0);
popMatrix();
}
}
void plotTrace()
{
stroke(255,80);
int inc = fftLog.avgSize();
if(record){//init dxf writing
out = createWriter("output.dxf");
out.println("0");
out.println("SECTION");
out.println("2");
out.println("ENTITIES");
}
for(int i=1; i<trace.length-inc; i++)
{
if(i%inc != 0)
{
beginShape(TRIANGLE_STRIP);
float value = (trace[i].z*100);
float m = map(value, -500, 20000, 0, 255);
fill(m*2, 125, -m*2, 140);
vertex(trace[i].x, trace[i].y, trace[i].z);
vertex(trace[i-1].x, trace[i-1].y, trace[i-1].z);
vertex(trace[i+inc].x, trace[i+inc].y, trace[i+inc].z);
vertex(trace[i-1+inc].x, trace[i-1+inc].y, trace[i-1+inc].z);
endShape(CLOSE);
if(record){//write each quad face to DXF file
out.println(" 0 ");
out.println("3DFACE");
out.println(" 10"); // first x
out.println(trace[i].x);
out.println(" 20 "); // first y
out.println(trace[i].y);
out.println(" 30 "); // first z
out.println(trace[i].z);
out.println(" 11"); // second x
out.println(trace[i-1].x);
out.println(" 21 "); // second y
out.println(trace[i-1].y);
out.println(" 31 "); // second z
out.println(trace[i-1].z);
out.println(" 12"); // third x
out.println(trace[i-1+inc].x);
out.println(" 22 "); // third y
out.println(trace[i-1+inc].y);
out.println(" 32 "); // third z
out.println(trace[i-1+inc].z);
out.println(" 13"); // fourth x
out.println(trace[i+inc].x);
out.println(" 23 "); // fourth y
out.println(trace[i+inc].y);
out.println(" 33 "); // fourth z
out.println(trace[i+inc].z);
}
}
}
if(record)//finish writing
{
out.println(" 0 ");
out.println("ENDSEC");
out.println(" 0");
out.println("EOF");
out.flush();
out.close();
record = false;
println("wrote DXF!");
}
}
}
void keyPressed()
{
if (key == 'r') record = true;
}
It's not super pretty, so feel free to encapsulate the functionality if you want, but it's not too bad either (it's still ASCII, human readable).
Here's a preview from Rhino (after rotating the mesh because Processing's coordinate system isn't the same):
