yMax = Double.MIN_VALUE;
yMax = -Double.MAX_VALUE;
	private void computeExtremums( )	{		xMin = Double.MAX_VALUE;		xMax = Double.MIN_VALUE;		yMin = Double.MAX_VALUE;		yMax = Double.MIN_VALUE;		zMin = Double.MAX_VALUE;		zMax = Double.MIN_VALUE;		for ( int i = 0; i < va.length; i++ )		{			xMin = Math.min( xMin, va[i].get( 0 ) );			xMax = Math.max( xMax, va[i].get( 0 ) );			yMin = Math.min( yMin, va[i].get( 1 ) );			yMax = Math.max( yMax, va[i].get( 1 ) );			zMin = Math.min( zMin, va[i].get( 2 ) );			zMax = Math.max( zMax, va[i].get( 2 ) );		}	}