# Isometric projection

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Isometric Projection

Isometric ProjectionIsometric projectionis a method for visually representing three-dimensional objects in two dimensions intechnical andengineering drawings. It is anaxonometric projectionin which the threecoordinate axesappear equally foreshortened and the angles between any two of them are 120 degrees.

Isometric TerminologyThe three coordinate axes are called isometric axesAny line parallel to isometric axes is called isometric line A non-isometric line is a line not parallel to any one of the three isometric axisIn isometric projection of cube, the faces of the cube and any plane parallel to them is called isometric planes

Isometric ScaleTrue lengths of the edges of the object are equally foreshortenedCorrect isometric projection can be drawn using an isometric scale (always smaller than ordinary scale)

*AEBO is isometric, cube is rotated to obtain AEBO (actual face of cube)

Isometric DrawingIsometric Projection: Drawing prepared with isometric scale on isometric axes

Isometric Drawing: Drawing prepared with ordinary scaleon isometric axes

*Compared to isometric projection, Isometric drawing has a chunkier overall impression

Steps for construction of Isometric :Step 1Isometric sketches begin with defining isometric axes, three lines, one vertical and two drawn at 30 from the horizontal.

Step 2Three lines of the isometric axes represent the three primary dimensions of the object: width, height, and depth

Step 3Draw the rest of the isometric block.

Step 4Add details to the block starting from the front face. Then add details to the other faces.

Step 5Darken all visible lines to complete the isometric sketch. (make sure that construction lines are light)

Axonometric projection shows all 3 dimensions, length, width and height.The isometric lines are only drawn to scale. Objects composed entirely of isometric lines can be drawn by taking all measurements parallel to main edges of the enclosing box.Non-isometric lines are drawn by transferring the ordinates (which are on isometric lines) of the end of the linesInclined and oblique surfaces are drawn using end coordinates. Box construction and offset measurements are common methodsIn an isometric drawing, an angle never appears in its true size. Angles, irregular curves require special techniques

Objects with Normal SurfacesMake an Isometric Drawing with corner A at the bottom

*Hidden detail is omitted unless it is necessary to show shape of object

*Hidden detail is omitted unless it is necessary to show shape of object

Objects with Oblique SurfacesMake an Isometric Drawing with corner A at the bottom

*Hidden detail is omitted unless it is necessary to show shape of object

Objects with Non-isometric LinesMake an Isometric Drawing with apex A facing front

Non-isometric lines are drawn with box construction and offset measurements

Non-isometric lines are not drawn in true length in isometric drawing (BA is shorter than CA in this drawing)

*Hidden detail is omitted unless it is necessary to show shape of object

Irregular ObjectsMake an Isometric Drawing of the following irregular object (pyramid)

OA and OB offsets help to locate apex O Complete box construction may not be needed in each

case

*Hidden detail is omitted unless it is necessary to show shape of object

Objects with Circular GeometryA circle in a orthographic projection will appear as an ellipse in an isometric drawing.Instead of actual ellipses often approximate ellipses are drawn for isometric drawing.Four-centre ellipses are used to approximate ellipses on isometric planes.

How to draw four-centre ellipse???

Draw the isometric centre lines of the circle. Using the centre lines, drawan isometric square with sides equal to the diameter of the circle.From the near corners of the box, draw two large arcs with radius R, using the two red points as centres. Draw the two smaller arcs with radius r, using two green points as centres.

Cylinder

Objects with Circular Geometry

*Hidden detail is omitted unless it is necessary to show shape of object

Objects with Non-Circular Curved SurfacesMake an Isometric Drawing of the following curved object

A line that appears as a noncircular curve in a normal orthographic view of an object appears as a non-isometric line in an isometric drawing.Curves may be drawn using a series of points by measuring along the normal lines in the orthographic view (offset measurements) and transferring these points on isometric drawing. Accuracy increases with number of points.

*Hidden detail is omitted unless it is necessary to show shape of object

Presented By

Enrollment No.Name130170111090RANA ABHIMANYU S.130170111091RATHAWA JAYDEVSINH130170111092RATHOR VIJENDRASINGH R.130170111094RATHWA VIKAS P.130170111090RUDRA PAWAN M.

Hope you enjoyed our presentation.Thank you

*AEBO is isometric, cube is rotated to obtain AEBO (actual face of cube)*Compared to isometric projection, Isometric drawing has a chunkier overall impression

*Hidden detail is omitted unless it is necessary to show shape of object*Hidden detail is omitted unless it is necessary to show shape of object*Hidden detail is omitted unless it is necessary to show shape of object*Hidden detail is omitted unless it is necessary to show shape of object*Hidden detail is omitted unless it is necessary to show shape of object*Hidden detail is omitted unless it is necessary to show shape of object*Hidden detail is omitted unless it is necessary to show shape of object

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