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The 3D graphic below shows a lectern - Leaving Cert DCG - Question A-1 - 2012
Question A-1
The 3D graphic below shows a lectern. The drawing on the right shows an incomplete trimetric projection of a similar lectern using the axonometric axes method. (a) C... show full transcript
Worked Solution & Example Answer:The 3D graphic below shows a lectern - Leaving Cert DCG - Question A-1 - 2012
Step 1
Complete the axonometric projection of the lectern.
Answer
- Projections from elevation and end view: Begin by defining the top view and front elevation of the lectern. Use the horizontal and vertical axes to denote the different planes of projection.
- Determining remaining 2 edges on sloping top (2 x 2): Identify the edges that are not fully expressed in the incomplete projection. Use parallel lines that correspond to the angles of the sloping sides.
- Determine points on curves (5 x 1): If the lectern has any rounded edges, plot points on the curve by assuming equal divisions, which allows smooth transitions between points.
- Draw correct curves: Connect the plotted points with smooth, continuous curves. Ensure the curves accurately depict the original features of the lectern.
- Draw horizontal brace: Detail the horizontal brace at the base, ensuring it aligns well with the overall structure.
- Draw right hand side of base: Finally, sketch the right-hand side base of the lectern, ensuring correct dimensions and alignment with the previously drawn elements.
Step 2
Determine and indicate the true diagonal length of the sloping rectangular top.
Answer
- Understanding of "diagonal" concept: Recognize that the diagonal length is the straight-line distance between two opposite corners of the rectangular top.
- Establish true shape of rectangular top: Utilize similar triangles and geometric principles if the top profile deviates from standard rectangles. Identify the sloping rectangle dimensions (length and width).
- Identify required true length: Apply the Pythagorean theorem. If the length is 'l' and width is 'w', then the diagonal 'd' can be computed as: d = rac{1}{2} \sqrt{(2l)^2 + (2w)^2} This formula helps in determining the true diagonal length based on the proportional relationship derived from the slopes.