GeometryInfo gi = new GeometryInfo(GeometryInfo.TRIANGLE_ARRAY);
gi.setCoordinates(tetrahedronCoordinates);
gi.setCoordinateIndices(coordIndices);
NormalGenerator ng = new NormalGenerator();
//The parameter specifying up to which angle normal vectors should be
//interpolated, is se here.
ng.setCreaseAngle(Math.PI);
ng.generateNormals(gi);
GeometryArray te = gi.getGeometryArray();
//Generate the tetrahedron as a Shape.
Shape3D tetrahedron = new Shape3D(te,yellowApp);