Student "edition" found at {csi dot journalspace dot com}.

Maybe I shouldn't have started this blog now, not with everything that's been going on.

On the ninth session of my Graphics Two class for the tenth week of classes (see the student copy for an explanation of the change of counting weeks) I gave them one plate again, this time getting the isometric from the incomplete orthogonal projections with slanted lines.

I came up with four different images for the two classes, again divided into two assignments each. And since they were told to bring larger papers this time, I made the figures at least four units high and wide.

Unlike the previous classes though, this day, even those who would usually get the final figures quickly were having difficulty, until I gave them hints using simple figures.

I said that if one view was slanted and another view was a block (no slanted line), then that means that the remaining view is also a block, and the isometric drawing looks like a wedge on one side.

But if the two views given are both slanted, then that means that the final view they have to get also contains a slanted line, either looking line a quarter of a pyramid cross cut from the top or a tetrahedron with two vertical sides.

That dual possibility actually makes it possible for some students to have a different image from the rest, yet still be correct. This is in fact hoped to create some confusion among those students who are not thinking through how the final figure is supposed to look, and just copy from their classmates. When they see the two different figures, hopefully they will try to think it through for themselves.

There were still some students from the first class who, not having the option above because I was still mainly in attendance in the classroom, who had a difficult time coming up with the final figure, and stayed in the room well into the second class.

I told them that since they were having difficulty with the basic concepts, I was going to give them special practice figures much like the supplementary problem sets in mechanics (one of these engineering majors is also my student in that class; not the first time that a student is enrolled in at least three classes that I teach for the term).

Either that, I said, or she was going to make a solid (if hollow) carton figure of some (or one relatively difficult single piece) of any of the drawings we’ve done.

She declined the extra work, but I still insisted on seeing some improvement in her analysis.

Session 857 also extended in class. We’re done for today.