Orthographic Projection n n Ortho perpendicular The system
- Slides: 27
Orthographic Projection n n Ortho -- perpendicular The system of drawing views of an object by projecting points perpendicularly onto projection planes. ¨ Projection lines represent line of sight ¨ Line of sight perpendicular to projection plane n Multiviews ¨ two-dimensional views of an object projected upon two or more planes of projection using orthographic projection techniques.
Orthographic projection
Multiview drawing of an object
Glass Box Model n. Place object in a glass box so the sides of the glass box are parallel to major surfaces of the object. n. Faces of the glass box serve as planes of projection n. Cut glass box along edges and unfold to obtain multiviews n Third-Angle projection - used in the US: ¨ Top view directly above the front view ¨ Right-side view to the right of front view
Glass Box Unfolding
Orthographic Views n Common projection planes (aka principal projection planes) ¨ frontal F front view ¨ horizontal H top view ¨ profile P right-side view Cut and open the glass box to get principal orthographic views n Other views: n ¨ bottom, rear, left-side
Dimensions necessary to define object: ¨ Height H -- FV & RV ¨ Width -- TV & FV ¨ Depth -- TV & RV n Alignment of views ¨ align n corresponding dimensions Represent hidden edges by dashed lines
Three space dimensions
Alignment of views
Selecting the Front View Represents the most natural position of use n Provides the best shape description or most characteristic contours n Has longest dimension n Has fewest hidden features n
Good orientation
Object suspended in a glass box, producing the six principal views
Unfolding the glass box to produce a six-view drawing
Most descriptive views
Types of Lines n Object lines (visible lines) ¨ solid lines ¨ represent visible surfaces or edges of the object n Hidden lines ¨ dashed lines ¨ invisible edges of the object n Centerlines ¨ long-short ¨ used n dashes to show centers of circles and arcs Others: extension, dimension, phantom, section, cutting-plane
Hidden features
Tangent partial cylinder
Nontangent partial cylinder
Line Precedence n When one type of line falls in line with a different line type, draw the line that is most important based on precedence: ¨ Object lines take precedence over hidden lines and centerlines. ¨ Hidden lines take precedence over centerlines. ¨ In sectioning, cutting plane lines take precedence over center lines.
Representing Planes n Normal Plane ¨ parallel to a principal projection plane ¨ can be seen in only one view as True Size n Inclined Plane ¨ tilted with respect to two principal proj planes ¨ seen in two views; not true size n Oblique Plane ¨ tilted with respect to all principal proj planes ¨ seen in three views; not true size
Fundamental views of surfaces
Rule of configuration of planes
Surface labeling
Numbering the isometric pictorial and the multiviews to help visualize an object
Orthographic Views in Auto. CAD n Group entities together into LAYERS. Use the layer manager to create layers. ¨ Object lines ¨ hidden lines ¨ section lines and hatching ¨ text and dimensions ¨ title border n Create rectangles for front, top, and right-side views ¨ use 3 rd angle projection ¨ appropriate spacing between views
OV with Auto. CAD n n Use horizontal construction lines to locate height dimensions common between FV and RV. Use vertical construction lines for width dimensions in FV and TV. Use a 45 -degree projection line (miter line) to transfer depth dimensions between TV and RV. Locate and plot projections of normal planes first, then inclined and oblique planes. Use solid lines for all visible object lines.
OV with Auto. CAD n n n Locate all hidden edges; use dashed lines. Locate centerlines of all circles and arcs. Check visibility of lines following precedence rules. Add dimensions and text. Import title block.
- Isometric view of machine parts
- Orthographic projection system
- Introduction of orthographic projection
- First angle projection
- Projection of solids cylinder
- The front view of a line inclined at 30°
- What is end view in engineering drawing
- Miter line in engineering drawing
- Orthographic drawing examples
- Glass box theory
- Sketching missing lines
- Hidden lines in orthographic projection
- Orthographic projection animation
- Hidden line orthographic projection
- Phantom line example
- Projection of points in different quadrants
- Orthographic projection
- Curved inclined plane
- Orthographic drawing title block
- Oblique vs isometric drawing
- Orthographic projection inclined surfaces
- Theory of orthographic projection
- Orthographic projection types
- Multiview drawing
- Dashed lines in orthographic projection
- Orthographic drawings architecture
- Orthographic projection cad
- Orthographic projection geology