Welp, you're in my house now! While a little over a year ago I passed on L3-5 to TAs in order to rebalance some of Drawabox's finances (we got hit by a significant loss of revenue at the time, and it made more sense to delegate the work and take a paycut, so I could redirect some time towards doing consulting work for my old studio), I still hold onto the last 4 mandatory steps of the course and the texture/chest challenges with a death-grip. For now.

ANYWAY! Let's jump right into it. Starting with your cylinders around arbitrary minor axes, I'm very pleased to see how much you varied your rate of foreshortening across all of these, and in doing so you've clearly demonstrated an either conscious and aware, or subconscious and intuitive understanding of how the two manifestations of foreshortening (the shift in scale from one ellipse to another and the shift in degree) operate together, rather than independently, to convey a consistent impression of how much of that cylinder's length exists in the unseen dimension of depth, and how much can be measured there right on the page. That is to say, you don't have any points where one of these shifts suggests a more dramatic rate of foreshortening, and the other suggests a shallower rate of foreshortening (which would be contradictory), but rather you keep it all sending the same message.

I'm also pleased to see that in marking out the true minor axis lines afterwards, you were quite fastidious in identifying both those with more noticeable discrepancies, and those that were only off by a little bit. This will help considerably when it comes to continuing to improve (rather than plateauing) as you fall into the "close enough" territory - which arguably you've been in for some time.

Continuing onto the cylinders in boxes, your work here is similarly well done, although there is one issue that I will call out in a moment in regards to your line extensions - but first I want to explain why the line extensions are important, and the purpose they serve.

As a whole this exercise is really all about helping develop students' understanding of how to construct boxes which feature two opposite faces which are proportionally square, regardless of how the form is oriented in space. We do this not by memorizing every possible configuration, but rather by continuing to develop your subconscious understanding of space through repetition, and through analysis (by way of the aforementioned line extensions).

Where the box challenge's line extensions helped to develop a stronger sense of how to achieve more consistent convergences in our lines, here we add three more lines for each ellipse: the minor axis, and the two contact point lines. In checking how far off these are from converging towards the box's own vanishing points, we can see how far off we were from having the ellipse represent a circle in 3D space, and in turn how far off we were from having the plane that encloses it from representing a square.

Now what I wanted to call out in regards to your line extensions is that I think you might be confusing how we approach marking out those lines in the previous section of the challenge (where we're really just identifying the orientation independently). Here however, our goal is to compare them with the lines extending off the boxes to see if they're all converging consistently, or more frequently, seeing where they're not. As such, it's important that you extend each line all the way back (rather than just marking them out on the ellipse itself) so you can have as easy a time identifying any discrepancies as possible. The fewer hurdles between us and the information we want our analysis the provide, the better.

Aside from that, there's just one other thing I noticed coming up in a few of your pages - so clearly not a widespread issue, but one worth noting. On this page as well as this page you opted to draw a bunch of boxes where all the vanishing points appear to be forced to infinity. This is actually not something that is possible when drawing in perspective projection, because a vanishing point being at infinity tells us the lines it governs are running perpendicularly to the viewer's angle of sight. Once you've got two of those sets of parallel edges perpendicular to the viewer's angle of sight, the last one can only run parallel to that angle of sight, so the vanishing point would be smack-dab in the middle of the box's silhouette, rather than at infinity.

Lesson 1 goes over this (moreso now than when you probably last went through it), but the notes here from the cylinder challenge itself touch on this as well, though more in the context of why forcing vanishing points to infinity for this challenge would not be appropriate, given that we're rotating them entirely randomly.

Anyway, be sure to keep those points in mind. I'll go ahead and mark this challenge as complete.