TOPICS
Object representation Multiview projection Glass box concept
Orthographic projection of point, line, plane, surface and object.
Line convention
OBJECT REPRESENTATION
Axonometric projection
- Multiview projection
MULTIVIEW PROJECTION
Three principle dimensions of an object …
… can be presented only two in each view.
| Length |
Adjacent view(s) is needed to fulfill the size dREPRESENTATION OF AN OBJECT
-
Revolve the object with respect to observer.
-
The observer move around the object.
Right side view
Top view
Front view
OBSERVER MOVE AROUND
Top view
Front view Right side view
THE GLASS BOX CONCEPT
Rear view
Left side view
Bottom view
Orthographic Projection of Object Features
Edge
Edges are lines that represent the boundary between two faces.
Corner
Corners Represent the intersection of two or more edges.
Edge No edge
No corner No corner
Surfaces are areas that are bounded by edges or limiting element.
Limiting element
is a line that represents the last visible part of the curve surface.
Surface Surface Surface
Surface Limit Surface Limit Line
True length
Point
True length
NORMAL LINE
True length
BT
Foreshortened
Foreshortened
INCLINED LINE
Edge
Edge
True size
Equal length
NORMAL PLANE
Foreshortened
Edge
Foreshortened
length
INCLINED PLANE
Foreshortened
Foreshortened
Foreshortened
OBLIQUED PLANE
s
Line Convention
LINE CONVENTION
Precedence of coincide lines.
Hidden line drawing.
Center line drawing.ble line
Order of importance
Hidden line should join a visible line, except it extended from the visible line.
No !
Hidden line should join a visible line, except it extended from the visible line.
Hidden line should intersect to form L and T
corners.
L T Correct
Hidden arcs should start on a center line.
In circular view, short dash should cross at the intersections of center line.
For small hole, center line is presented as thin continuous line.
Leave space
Center line should not extend between views.
Leave space
Leave the gap when centerline forms a continuation with a visible or hidden line
Center line should always start and end with
long dash.
Leave space
Leave
