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Section Views. Lecture 13. Topics For Today. Sections Views Why section views are needed Types of section views References BTG Chapter 6. Section Views. Goals Recognize various kinds of section views, make full and half section views. Improve visualization of interior features.
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Section Views Lecture 13 Autumn Quarter
Topics For Today • Sections Views • Why section views are needed • Types of section views • References • BTG Chapter 6 Autumn Quarter
Section Views • Goals • Recognize various kinds of section views, make full and half section views. • Improve visualization of interior features. Autumn Quarter
Section views are used when important hidden details are in the interior of an object. These details appear as hidden lines in one of the orthographic principal views; therefore, their shapes are not very well described by pure orthographic projection. Section Views Autumn Quarter
Types Of Section Views • Full sections • Half sections • Offset sections • Revolved sections • Removed sections • Broken-out sections Autumn Quarter
Cutting Plane • Section views show how an object would look if a cutting plane (or saw) cut through the object and the material in front of the cutting plane was discarded Autumn Quarter
Section Lines • Section lines (crosshatching) are used to show where the cutting plane passed through solid material Autumn Quarter
Hidden Lines are Visible Full Section View • In a full section view, the cutting plane cuts across the entire object • Note that hidden lines become visible in a section view Autumn Quarter
Full Section View • Shows cutting plane in the top view • Makes a full section on the front view Autumn Quarter
Visible lines omitted Incorrect Correct Full Section View • Note how the cutting plane is drawn and how the crosshatching lines mark the surfaces of material cut by the cutting plane. • No hidden lines on the section view, if possible. • Note: Interior lines behind cutting plane became visible. Autumn Quarter
SECTION A-A B A A SECTION B-B B Multiple Sectioned Views Autumn Quarter
Half Section View The cutting planes do not cut all the way through to the object. They cut only half way. They intersect at the centerline. Autumn Quarter
Half Section View • Half Section used mainly for symmetric objects Autumn Quarter
Revolved Sections • Revolved sections examples show the shape of an object’s cross-section superimposed on a longitudinal view Autumn Quarter
A Section B-B A Section A-A B B Section C-C C C Removed Sections Removed sections are like revolved sections but moved aside. Note how they are named. Autumn Quarter
Broken Out Sections Autumn Quarter
Offset Sections Offset sections are used to show interior features that do not lie along a straight line Autumn Quarter
Offset Sections Autumn Quarter
Conventional Revolutions • Used to make section views clear and avoid confusion • Associated with objects that have holes, ribs, spokes, or lugs in any combination equally spaced in a circular fashion • Not projected orthographically to section view • Examples to follow Autumn Quarter
Conventional Hole Revolutions • Note no hidden lines Autumn Quarter
Conventional Rib Revolutions • Note: Ribs not crosshatched Autumn Quarter
Note: Spokes not crosshatched Conventional Spoke Revolution Autumn Quarter
Holes and Ribs in Combination Autumn Quarter
Assignment • Dwg 25 – F18-A • Complete section views • Due at end of today’s lecture • Dwg 26 – SECT 1-N • Sketch Section Views • Due at beginning of next lecture Autumn Quarter