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Isometric ellipses. In an isometric drawing, the object is viewed at an angle, which makes circles appear as ellipses. Holes Cylinders. Sketching a Circle. Draw a square whose sides are the diameter of the circle. At the center of each side define the point of tangency for the circle.
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Isometric ellipses • In an isometric drawing, the object is viewed at an angle, which makes circles appear as ellipses. • Holes • Cylinders
Sketching a Circle • Draw a square whose sides are the diameter of the circle. • At the center of each side define the point of tangency for the circle. • Draw the diagonals of the square. • Orient the paper so you can draw equal arcs to construct the circle
Introduction to Isometric Projection CUBE • Isometric means equal measure • All planes are equally or proportionately shortened and • tilted • All the major axes (X, Y, Z) are 120 degrees apart
60o 60o 30o 30o Isometric Axis • Making an Isometric Sketch • Defining Axis
Diameter Diameter Length Step 1 – Creating the Base Box
- Corner to corner to get center - Lines to tangent points Tangent Points Lines to Tangent Points Step 2 – Ellipse on Front Face
Sketch in Arcs Tangent Points Step 3 – Ellipse on Front Face
Repeat for ellipse on rear face Draw Tangent Lines for Profile Complete Visible Part of Back Ellipse Step 3 – Ellipse on Back Face and Profile
Create Box for Hole Sketch Ellipse Step 4 – Ellipse for Hole on Front Face
Summary • Technical drawings are an effective communication media • Projections of various types can be used • Isometric projections and creating isometric sketches has been introduced • Assignments will emphasize simple isometric sketches
Review Questions b) c) d) a) 120° 60° 60° 90° 60° 120° 120° 240° • _______ sketches present the object in a single view, with all three dimensions represented • _______ sketches present the object in a series of projections, each one showing only two of the objects’ three dimensions • Which among the following is NOT an isometric axes (Hint: Use the Isometric Grid paper for reference)?
Tips for Drawing Assignments • Follow Sketching and Text conventions. • Title Information is required. Avoid labels on the sketch. • Leave the construction lines – MUCH lighter and thinner than the finished lines • Include centerlines on isometrics
Tips for Drawing Assignments • Do not try to shade drawing – this is not a pencil sketching class. • Use grid paper. Try to sketch along grid lines. Practice sketching straight lines and curves on a grid sheet.
Tips for Pictorial Views • In pictorial views, hidden lines are not shown unless absolutely required for clarity, such as; • Non-visible bottom of a blind hole • Important feature of object not in direct view • In pictorial views, holes or notches without bottom/end visible should be assumed to go completely through the object. • Centerlines are to be shown on all isometric pictorials.
In Class Assignment • Use Isometric Sketch Paper (ISP)