Overview
This lecture explains how to select, arrange, and draw orthographic projection views of an object, including transferring dimensions and finalizing the drawing layout.
Selecting Views for Orthographic Projection
- Typically, three views are enough to represent an object in orthographic projection.
- Choose views that show the most features with the fewest hidden lines.
- For the example object, the top, front, and right views are best.
Arranging Views on Paper
- Proper view arrangement avoids wasted paper and crossing into the title block.
- An alternate arrangement of the right view, unfolded away from the top view, often uses space better.
Drawing the Views
- Decide on the drawing scale (often 1:1) and lay out the views before drawing.
- Draw datum lines for each view, considering relationships and space for dimensions.
- Begin with the top view, using previous techniques.
Transferring Dimensions Between Views
- Measure height dimensions directly in the front view from the datum line.
- Mark visible surface heights and draw parallel lines for these.
- Project width points from the top view into the front view to draw features.
- Use dashed lines to represent hidden features.
- Draw an auxiliary line to project height dimensions from the front to the right view.
- Transfer depth dimensions from the top view into the right view.
Completing the Drawing
- After constructing all features, darken visible outlines and hidden lines.
- Erase unnecessary construction lines.
- Add dimensions, ensuring not to repeat them in multiple views unless needed.
- Check for and erase stray marks to keep the drawing clean.
- Fill out the title block information before considering the drawing complete.
Key Terms & Definitions
- Orthographic Projection — a method of representing three-dimensional objects in two dimensions using multiple views.
- Datum Line — a reference line for measuring and projecting features between views.
- Hidden Line — dashed lines representing features not visible from a particular view.
Action Items / Next Steps
- Practice drawing orthographic projections using top, front, and right views.
- Ensure dimensions and title block information are included in your drawings.