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04-BS-15 · December 2017

Question 2 of 5: Isometric view from a multiview drawing

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

Notes on this paper

National Exams, 04-BS-15 Engineering Graphics & Design Process, 2017-Dec. Closed-book, no calculator; five questions constitute a complete exam paper, and all sketches must be freehand (no straightedge).

Reference texts: Bertoline & Wiebe, Technical Graphics Communication (4th ed.) — orthographic projection, isometric pictorials, section views, dimensioning; Giesecke et al., Technical Drawing / Engineering Graphics (15th ed.) — ASME Y14.5 / CSA B78.2 GD&T, dimensioning, and constructive solid geometry (Boolean primitives). ASME Y14.5-2018, Dimensioning and Tolerancing — geometric tolerancing feature-control-frame conventions.

Question 2: Isometric view from a multiview drawing (10 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

[Figure not reproduced: Exam figure, page 3: TOP (upper left), FRONT (lower left), RIGHT-SIDE (lower right), third-angle. See the official exam paper or the cited reference text.]

Exam figure, page 3: TOP (upper left), FRONT (lower left), RIGHT-SIDE (lower right), third-angle.

Reading the views. The top view sits above the front view and the right-side view to its right, so the drawing is third-angle. In the side view, the edge nearest the front view is the object’s front face. The overall block is about 10 : 5 : 6 (length : depth : height) and the plate thickness is about 1 unit. Reading together:

  1. Top flange. A plate 1 thick runs along the top from the left end to the vertical wall. It has a vertical through-hole of about ⌀2.5 centred in its width and depth: a visible circle in the top view, and hidden lines through the flange in the front and side views.
  2. Vertical wall. About 1 thick, full height and full depth, standing at 40–50% of the length. Its left face under the flange shows as the dashed line in the top view; its top-right edge is the visible line beside it.
  3. Base plate. 1 thick, running from the foot of the wall to the right end. Its top is the lower horizontal line in the front and side views.
  4. Triangular rib in the back half only. The front view’s diagonal runs from the top of the wall to the right end of the base. The rib covers only the back half of the depth, for two reasons. First, the front view shows a visible vertical line at the wall’s right face; if the rib were flush with the front, the wall and rib front faces would be coplanar and that line would not exist. Second, the top view has a line at mid-depth over the rib region, and the side view has a vertical line at mid-depth: that is the rib’s set-back front face seen edge-on. The dashed line in the side view is the flange underside, hidden behind the wall.

Isometric construction (axes 120° apart, lengths transferred directly from the views):

  1. Box in the whole object, 10 × 5 × 6.
  2. Cut away the lower-left block under the flange, leaving flange, wall and base as an L-shape.
  3. Draw the rib as a triangle on the plane at mid-depth, running from the wall top down to the right end of the base, with its inclined face going back to the rear face.
  4. Draw the hole as an isometric ellipse on the flange top, including the visible part of its far lower edge.
  5. Darken the visible edges; hidden lines are normally omitted in a pictorial.
Isometric (viewer front-right-top); hidden lines omitted
Fig. Q2 — isometric: top flange with vertical hole, wall, base plate, and the triangular rib set back in the rear half of the depth.