Architectural Symmetry!

BASICS

     Isometric is from the word "iso" which means equal and "metric" which is measure. Isometric drawings are a form of drawing that projects an object in picture form for better clarifying the objects appearance. Isometric drawings also resembles a picture of an object that is drawn into 2 dimensions. As an effect, existing AutoCAD commands -- such as line and copy are used to produce isometric drawings. Isometric basics include regular, angular and circular objects that are drawn in isometric form. Isometric drawings are consist of 2D drawings that are tilted at some particular angle to expose other views or planes and give the viewers the illusion that what he or she is currently viewing is a 3D drawing. The tilting occurs with two 30 degree angles that are struck from the intersection of a horizontal baseline and a vertical line. The directions formed by the 30 degree angles that will going to represent actual dimensions of the object; that are maybe either width or depth. Vertical lines in most cases represents the height dimension. Once the horizontal baseline and the vertical line are drawn, the 30 degree angles are projected from this common point which becomes the reference point of the isometric view. Once the 30 degree lines are drawn, the baseline is no longer needed and it is usually discarded through erasing it. Depending on how we viewed the drawing or the object rather, width and depth measurements are made along the 30 degree lines and height is also measured along the vertical line, All isometric drawing has a width dimension that measures to the right along with the 30 degree angles.

CONSTRUCTING THE BASICS

     Any Isometric drawings no matter what or how simple or complex, has an overall width, height and depth dimension. Start laying out the drawing with these 3D to create an isometric box. Some techniques rely on piecing the isometric together by views, unfortunately it is very easy to get lost in all of the lines using this method. Once a box is created from overall dimensions, somewhere inside the box is the object. You can also use the left, top or even the right isometric axis modes to assist you in your constructing process.

CREATING AN ISOMETRIC GRIDS

     In manual drawing and sketching days before, an isometric grids was used to layout lines before the lines were transferred to paper or to the Mylar for ink and pen illustrations. An isometric grid may defined in an AutoCAD drawing through the  snap command. Choosing an isometric style of snap may vary display from orthographic form. The grid distance changes to a vertical spacing height that you specify. To see how vertical spacing distance affects the grid, changing it to isometric form, the dot A becomes the reference point point where the horizontal baseline is followed by the vertical line represented by the dot B, At dots A and B, 30 degree lines are drawn point C and D are formed where they intersect. This is how an isometric screen display is formed..

CONSTRUCTING ISOMETRIC ARCS

     The ellipse command – can also be used to draw an isometric arc of any included angle. To construct an isometric arc, use the arc option, go to the ellipse button on the draw toolbar and then enter A, enter El or Ellipse at the command. Once the arc option is initiated the following prompts will appear:

•          Specify axis endpoint of elliptical arc: (center/isocircle)
•         Specify center of isocircle: (center of the arc)
•         Specify radius of isocircle (diameter): (pick the radius and enter)
•          Specify start angle (parameter): (pick a start angle and enter)
•          Specify end angle : (pick an end angle and press enter)

    A common application of isometric arcs is drawing fillets and rounds. Once a round is created isometrically, the edge (corner) of the object from its original will unfiltered its position. You  can draw the complete object first then trim away the excess when you finally located the fillets and draw the lines of isometric arcs.