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The 3D graphic below shows a road sign and its supporting frame - Leaving Cert DCG - Question A-2 - 2012
Question A-2
The 3D graphic below shows a road sign and its supporting frame. The supporting frame is in the form of a regular tetrahedron. The drawing on the right shows the p... show full transcript
Worked Solution & Example Answer:The 3D graphic below shows a road sign and its supporting frame - Leaving Cert DCG - Question A-2 - 2012
Step 1
Complete the elevation. (i) Elevation of parallelogram shaped outline.
Answer
To complete the elevation of the parallelogram-shaped sign, we need to project the vertices from the 3D view onto the elevation plane. Identify the corners of the parallelogram and ensure that the dimensions are proportional to the original shape. Mark the proper elevations of the vertices in a vertical plane to reflect their true positions.
Step 2
(ii) Elevation of rear support leg.
Answer
The elevation of the rear support leg can be determined by extending a vertical line down from the top vertex of the tetrahedron to the ground plane in the elevation view. This will create a vertical line representing the support leg's height, maintaining the appropriate angle with respect to the ground.
Step 3
(iii) Determine points on arrow in elevation.
Answer
For the arrow, identify its base and top points from the 3D representation. Project these points in alignment with the perspective from the elevation. The base should align with the base of the parallelogram, while the tip of the arrow extends appropriately to indicate direction.
Step 4
(iv) Draw arrow (Any = 1).
Answer
To represent the directional arrow effectively in the elevation view, draw a straight line for the shaft of the arrow leading to a pointed shape at the end. Ensure that the arrow maintains its proportions relative to the parallelogram sign, and position it accurately to indicate the intended direction.
Step 5
Determine the true shape of the sign. (Identify true shape of triangular face.)
Answer
The true shape of the triangular face can be established by projecting the coordinates of the triangle vertices onto the nearest reference plane. Measure the lengths of the sides and ensure correct angles; this will yield the accurate outline of the triangular face when viewed orthographically.
Step 6
(vi) Determine true shape of parallelogram.
Answer
To find the true shape of the parallelogram, project each vertex onto a plane parallel to the parallelogram face. Measure the lengths and the angles created by the vertices. The resulting shape should reflect the actual dimensions and angles of the parallelogram as viewed in 3D.