Construct and interpret plans and elevations of 3D shapes (2)
In this second set of tasks involving plans and elevations, the 3D objects are more complex and we make use of isometric paper for their 3D view. We pay particular attention to the conventions used to represent visible and hidden edges when drawing plans and elevations.
MONDAY: It is quite challenging to visualise this somewhat
peculiar shape and students might take a while to appreciate the subtle
differences between the two given elevations. Students might find it helpful to make the shape from interlocking cubes.
Consider the edges marked in red and with the broken brown line (below, left). An important issue here is how we represent them when they are visible (as in the case of the brown edge in the elevations from A and B) or not visible (as in the case of the brown edge in the elevations from C and D, and the red edge in the elevation from B). We have adopted the convention that hidden edges are ignored, but you might want to use another convention (such as the use of broken or thinner lines).
WEDNESDAY: This is a fairly straightforward task, but students might at first think there is only one way of arranging the 11 unit cubes.
THURSDAY: This is a fairly classic 'viewpoint' task. Students will need isometric paper, or they could be asked to make a freehand sketch on plain paper.
FRIDAY: Here we see the 3D view of the F-shape that students were asked to draw in Thursday's task. The elevation of the F-shape needs to be interpreted with care as the view is not square-on but at a 45˚ angle to the vertical faces of the shape.
The elevation from Dan's position is similar to Cori's, but with subtle differences:
