Isometric Drawing
A pictorial representation of an object in which all three dimensions are drawn at full scale rather than foreshortening them to the true projection. An isometric drawing looks like an isometric projection but its all lines parallel to the three major axes are measurable. An isometric view of an object can be obtained by choosing the viewing direction in a way that the angles among the projection of the x, y, and z axes are all the same, or 120°.
Any engineering drawing should show everything - a complete understanding of the object should be possible from the drawing without any need for explanations. If the isometric drawing can show all particulars and all dimensions on one drawing, it is best of all. The representation of the object seen here is called an isometric drawing. This is one of a family of three-dimensional views called pictorial drawings. In an isometric drawing, the object's vertical lines are drawn vertically, and the horizontal lines in the width and depth planes are shown at 30 degrees to the horizontal. When drawn under these guidelines, the lines parallel to these three axes are at their true (scale) lengths. Lines that are not parallel to these axes will not be of their true length. Method of graphic representation of three-dimensional objects, used by engineers, technical illustrators, and, occasionally, architects. The technique is intended to combine the illusion of depth, as in a perspective rendering, with the undistorted presentation of the object’s principal dimensions, that is, those parallel to a chosen set of three mutually perpendicular coordinate axes.
Isometric drawings try to get used to ‘flipping’ the set-square over keeping the longest edge in contact with the horizontal motion bar. Always keeping the ‘sharpest’ (narrow angle) part pointing either left or right. Only when a 90 degree angle is needed can the sharpest (narrow) angle of the set-square point to the top of the page. 3D Isometric drawings are based on mathematical systems and it tries to convey a larger degree of realism by applying perspective to the drawing.