Sketching By Brian Nettleton This material is based upon work supported by the National Science Foundation under Grant No Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).

Oblique In an Oblique sketch, the front view is flat and sketched true size. The depth is sketched at a 45 degree angle. The lines on the grid paper are used for reference. Each square on the grid is ¼” and the lines are vertical, horizontal, and at a 45 degree angle. Starting at the lower right hand corner of the sketch, sketch the length of the front view, the depth of the object on the 45 degree angle line, and the height of the front right corner.

Oblique Sketch the front view of the object. These lines should be horizontal and vertical.

Oblique After the front view is complete, begin creating the depth by sketching the side and top views. It is sometimes easier to sketch the 45 degree angle lines first and then add the vertical and horizontal lines to form the back of the object.

Oblique To make the sketch more presentable, erase any stray lines and clean up the corners to make them sharp.

Isometric An Isometric grid has vertical lines for height and 30 degree angle lines for width and depth. One way to create a sketch is to use the total height, width, and depth, and make a box, Start at the front corner of the object and sketch the lines for the height, width and length. Now square off the front, top, and sides of the box.

Isometric Sketch in the lines that define the side view. The box helps to show where the different views belong in the sketch.

Isometric Now sketch the lines that define the front and top views.

Isometric To finish up the sketch, erase the construction lines and cleanup the corners.

Orthographic Projection Orthographic projection is a 2- dimensional representation of a 3-dimensional object. When sketching an Orthographic Projection drawing, the front view needs to be sketched first. Any side of the object can be considered the front view. The side that shows the most detail and the fewest hidden lines should be the first choice. All of the views should be sketched actual size or the same scale.

Orthographic Projection The lines that define the right side of the object need to be projected to the right side of the paper. The vertical lines that define the width of the object need to be sketched next.

Orthographic Projection The side view is now completed. The top view can be done without any further measuring. Above the side view sketch a line at a 45 degree angle. This is called 3 rd angle projection. Sketch construction lines from the sides of the side view up to the angled line.

Orthographic Projection At the points where the vertical construction lines intersect the angled line, sketch horizontal lines over the top of the front view. Sketch vertical construction lines from the front view at the points that define the top view up through the horizontal lines.

Orthographic Projection Darken all of the lines that define the object in each view and erase all of the construction lines.

Standards and Benchmarks Standard 11: Students will develop abilities to apply the design process. J. Make two-dimensional and three-dimensional representations of the designed solution. Standard 17: Students will develop an understanding of and be able to select and use information and communication technologies. K. The use of symbols, measurements, and drawings promotes clear communication by providing a common language to express ideas.