docs: public double estimateExcludedVolumeFraction(){
  		//Calculate volume/area of the of the scene without obstacles
  		if(recalculateVolumeFraction){
  			CentralRandomNumberGenerator r = CentralRandomNumberGenerator.getInstance();
  			boolean firstRandomDraw = false;
  			if(randomNumbers==null){
  				randomNumbers = new double[nRandPoints*dimension];
  				firstRandomDraw = true;
  			}
  			int countCollision = 0;
  			for(int i = 0; i< nRandPoints; i++){
  				double[] pos = new double[dimension];
  				for(int j = 0; j < dimension; j++){
  					if(firstRandomDraw){
  						randomNumbers[i*dimension + j] = r.nextDouble();
  					}
  					pos[j] = randomNumbers[i*dimension + j]*size[j];
  				}
  				if(checkCollision(pos)){
  					countCollision++;
  				}
  			}
  			fraction = countCollision*1.0/nRandPoints;
  			recalculateVolumeFraction = false;
  		}
  		return fraction;
  	}