There's a reason this lesson's considered the big boss - where other lessons certainly demand a lot, and expect students to put in many hours, the sheer difference in magnitude of the time that goes into each drawing here is definitely a big jump. Looking at the time estimates you added to your drawings (thanks for that by the way), you're definitely putting a good chunk of time into each drawing, and that's great. I will say this - the amount of time you put in is totally normal. I have had students who've invested even more time - for example, LordNed's submission had him spending upwards of 9 hours on some of his drawings. I definitely don't expect that from students, but it is always good to see the way in which that time can be spent. When it comes to construction and pinning down all the specific subdivisions and whatnot, there is much work to be done.

Anyway, let's get started. Starting with your form intersections, you are largely doing a great job of demonstrating a strong grasp of how these forms relate to one another in 3D space. Your boxes are decent, though I do think more can be done to think through how each line needs to be oriented, relative to the other lines of its set, in order to converge consistently together, but your linework is confident and the approximated convergences aren't too bad. The intersection lines themselves are looking great though, and it shows that you've come a long way since your first stab at lesson 2.

Jumping ahead to your vehicle constructions, by and large the methodology by which you approach these constructions is quite solid. There are issues in some of them, but the trend is essentially that when you stick to the construction, your drawings turn out better, and when you take liberties and jumps of complexity that aren't really supported, your work suffers.

For the various demo drawings, you've shown a lot of patience and care, and the capacity to build these out to achieve solid results. You push deep into details without abandoning constructional principles - always working in form, making sure you pin down the correct subdivisions and all to ensure the details you do construct are positioned specifically where they need to go.

We can see this carrying over into all of your vehicle constructions, but the main difference is that in a number of the drawings, you sometimes seem to decide, "construction's done, let's have some fun!" - for example, this camaro demo drawing definitely marks a bit of a difference from your other demo drawings, where it seems you decide to abandon your construction fairly early on, once you've got the major proportions down. Admittedly, that is more than a little bit my own fault, because the demonstration itself could certainly be better. That said, there still are a lot of ways in which this late stage still adheres to the structure.

My real mistake was the fact that back when I created this demo, I was still not entirely clear on how I wanted to teach this course, and so I, like most students, fell towards making things look pretty in the end. The mustang demo definitely pushes the adherence to construction way farther. When I decided to keep the camaro demo around, I did add the disclaimer at the top pointing out that it's very old (from 2016), but still valuable in many ways. It should still be superceded by the mustang demo in pretty much every way.

I am currently embarking on redoing all the video content of the course, starting from Lesson 1 (I've got the videos for Lesson 1: Lines recorded but a few pieces still need to be edited before I can push them out), so in the coming months I hope to remedy this issue completely, without any straggling old bits hanging on.

As a side note - the whole "splotches of black" rendering style I used in the camaro, which you applied to a number of your drawings, should probably be left aside. It's honestly just not needed - proper structure stands for itself, and more and more I find that when we rely on rendering like that, it's because the structure isn't strong enough.

Anyway, I've gotten off topic here. My main point is, stick to construction throughout the entire process, and avoid allowing yourself to find the point where you say "construction's over". Construction is never really over - we can always push it further while still clinging to that base structure and building directly on top of it. The moment we set construction aside and go back to treating our drawing like, well, a drawing, is when we start undermining elements of its solidity.

To that point, you definitely have a number of constructions that cling to construction well. For example, this firebird has excellent structure and maintains specific curvature and profile. This Mercury Comet maintains its structure quite nicely too, though the car itself leans into it being boxy as it is. I even think drawings like this one and this one do a great job, and they show that it isn't ultimately about detail. As long as you're still holding to the structure firmly and haven't gone back to treating it like a 2D drawing, it'll still maintain that excellent sense of solidity.

So, I am definitely pleased with the overall progress you're showing, but before I mark this lesson as complete, and with it the entire course, I want to see one more car drawing from you. I want you to give this one everything you have, to really push the limits of your already impressive patience, and to see just how far it can be pushed. Don't work in really long continuous stretches, as you did for some of these. Spread it out over a few days, and take lots of breaks. Looking at LordNed's work, which I linked earlier, may help serve as motivation as well, because I guarantee you can produce work that good as well.

One other thing - definitely put more time into studying the proportions of your cars with orthographic proportional studies. You may well be doing this already, but the proportions are still a bit iffy, so investing more of your time to really pin that down will help immensely.

I look forward to seeing what you can produce!