January 18th, 2018

posted Jan 19, 2018, 8:07 AM by Mr Becker



IsoDetailed


Pictorial drawings show the shape of an object viewed by the human eye. Pictorial sketches are sketches that show height, width, and depth all in one view. Common types of pictorial drawings are isometric and perspective.


An isometric sketch shows an object in which the width and depth are projected at 30 degree angles from the horizontal axis. The height, width, and depth values are all at the same scale. A technique that you can use when making an isometric sketch is to use isometric grid paper. This helps with determining the correct angle for your sketch.


Perspective is a way to draw that shows a view of the object in the most realistic way. Vanishing points are used to guide the lines in the object to the horizon line or the horizontal line that you see at your line of sight. In a one-point perspective, all lines in the depth project to one point (the vanishing point). For example, when you look down a long, straight train track, it appears that the track eventually narrows until it vanishes. In a two-point perspective, the width lines converge on one vanishing point, and the depth lines converge on the other vanishing point. Think of standing at the corner of a city block; the buildings vanish in both directions.


Pictorial sketches help engineers explain ideas and communicate to the customer what the final part will look like. Unfortunately, pictorial drawings have some disadvantages. Foreshortened views and distorted features do not allow for accurate prototyping. In order for parts to be accurately depicted, you typically need views that directly portray each surface. In order to obtain these straight line views, we have a type of drawing called orthographic projection, also known as multiview drawing. Orthographic projection is a way to project a view based on a line of sight that is perpendicular to that view. Orthographic drawings are said to show true size and shape.


Watch this presentation on Sketching Practice


We will use what you have learned to complete this Sketching Practice worksheet

Make a copy of this sheet (file, make a copy) to your google drive, and use that one to complete the assignment.


If you have access to a printer, you may go ahead and get a head start on this.  If not, you will have the opportunity to do them it in class next time we meet.


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