Accumulationsbuffer

Hi, for many hours I try to implement anitaliasing using the accumulation buffer. However I could not get it started until now. this is my code: private void rendering() { Gl.glEnable(Gl.GL_BLEND); Gl.glEnable(Gl.GL_LINE_SMOOTH); Gl.glEnable(Gl.GL_MULTISAMPLE); Gl.glHint(Gl.GL_LINE_SMOOTH_HINT, Gl.GL_DONT_CARE); Gl.glBlendFunc(Gl.GL_SRC_ALPHA, Gl.GL_ONE_MINUS_SRC_ALPHA); Gl.glEnable(Gl.GL_DEPTH_TEST); Gl.glClearColor(0.350f, 0.350f, 0.350f, 1.0f); Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT); Gl.glClearAccum(0.0f, 0.0f, 0.0f, 0.0f); Gl.glClear(Gl.GL_ACCUM_BUFFER_BIT); int i,j; int min = -1; int max = +1; float scale = 0.5f; for(j = min; j <= max; j++) { for(i = min; i <= max; i++) { Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT); Gl.glMatrixMode(Gl.GL_MODELVIEW); Gl.glLoadIdentity(); Gl.glTranslatef((float)(i*scale), (float)(j*scale), 0.0f); drawScene(); Gl.glAccum(Gl.GL_ACCUM, 1.0f/9.0f); } } Gl.glAccum(Gl.GL_RETURN, 1.0f); Gl.GlFlush(); } Using this code it does not work, there are no changes like I would not use the AccumBuffer. Do I have to set something else enable or did I forget anything important? I would be really pleased if someone could help me. Thx in advance, Stefan