The eye transformation allows to use the coordinates relative to the viewer:
void setup() { fullScreen(P3D); } void draw() { // draw scene... pushMatrix(); eye(); translate(0, 0, 100); ellipse(0, 0, 50, 50); popMatrix(); } One can retrieve the matrix holding this transformation:
PMatrix3D eyeMat = new PMatrix3D(); void setup() { fullScreen(P3D); } void draw() { // ... getEyeMatrix(eyeMat); // ... }