chapter 5 orthographic projection Flashcards
the three dimensions of an object are
width height depth
the six standard views or six principal views
front top right side
left side rear bottom
views that show width
front top bottom rear
views that show height
front
left side
right side
rear
views that show depth
top left side right side bottom
orthographic means
at right angles
three planes of projection
frontal
horizontal
profile
frontal plane
front and rear
horizontal plane
top and bottom
profile plane
right and left
when determining necessary views
choose the views that have the least amount of hidden lines and show essential contours and shapes clearly
complicated drawings may require more than
three views
when a surface is perpendicular to the plane of
projection,
it will project an edge view of the surface.
when a surface is parallel to the plane of projection
the surface will project true size and true shape
when a surface is inclined to the plane of projection
the surface will project foreshortened
the three regular view are
top
front
right side
third angle projection
USA
as if the observer is outside, looking in.
First angle projection
Europe
right side is the the left of front view
top is below front
when an edge is perpendicular to the plane of projection,
the edge will project as a point
when an edge is parallel to the plane of projection
the true length of the edge will be projected
when an edge is inclined to the plane of projection
the edge will appear foreshortened
centerlines composed of
three dashes one long at each end and on short in the middle
centerlines show
page 174
the axis of symmetry
indicate a path of motion
show location for circular patterns
correct practice for hidden lines
page 175
leave a gap when a continuation of a visible line
hidden lines intersect at L and T corners
they jump a visible line
parallel hidden lines are staggered
