Alrighty, let's get started. Looking at your form intersections, your work here is generally looking pretty good, albeit some of the box constructions are a little off (like the one in the bottom right corner, where you marked your own little question mark - though I suspect you may have drawn it that way because you hit the edge of the page). One suggestion I do have however is that when drawing the contour lines, just for the sake of simplifying this exercise, you don't need to draw the intersection all the way around. I know I generally stress the importance of drawing through forms, but in this case it does start to get a little distracting. That said, you did handle them quite well all the same.

Your cylinders in boxes are a bit on the looser end - don't forget to draw through your ellipses two full times, and be sure to apply the ghosting method before executing them to help improve your overall control and keep those ellipses more snug within the enclosing plane.

Now, moving onto your vehicle constructions, there is definitely a lot of good here, but also some key areas where your approach can be adjusted to yield better results. To start, I did notice that you don't seem to have necessarily used an ellipse guide, instead opting to freehand a lot of your ellipses. I know that you did have an ellipse guide throughout the wheel challenge, so the choice not to use one for many of the wheels (which were generally smaller and should have been in the range you had available to you), was definitely a strange one. Taking that further, I noticed that you didn't opt to use the technique explained in this section, where we use ellipses to establish squares in 3D space, and then extend them into "unit" cubes to help us build out our three dimensional object to a specific scale. In this case using ellipse guides would be extremely useful, as it would allow for much more precision in building out those squares in 3D space.

Now, that aside, it's clear that you did employ a great deal of subdivision throughout your constructions, and you clearly put a lot of effort into observing your references closely. There were definitely some issues with proportion, but that was primarily because you missed that one important technique I mentioned above. Your proportional studies went into a fair bit of detail, pinning down the relationships between a lot of these different forms.

To that point however, there was another key issue that held you back. It's not that you didn't have a lot of excellent drawings, but that in drawing them, there were still a lot of leaps of logic you were making - a lot of forms that were placed or aligned in a more arbitrary fashion.

The thing about this lesson is that it really demands a lot from students, and pushes us to ensure that every single constructional step we take is solidly supported by the phase preceding it. The easiest thing to place in the world is a box, because it hinges on subdivision very easily. And so, every cylinder should first have its positioning in the world established as a box. If we look at this wheel for instance, you did establish the plane in which that ellipse would sit, but you didn't construct the entire form, and as a result you were still doing a fair bit of guesswork there when pushing it into the third dimension.

Calling back to Lesson 6, there's a particular section there that you may have forgotten about curves. Specifically the fact that when we just draw an arbitrary curve in the world, it's rarely going to feel all that solid, because of how vague it seems. Instead, creating a scaffolding for that curve using straight lines (or in the case of working in three dimensions, creating a "boxy" version of the form with flat planes) will help immensely in pinning down more specific, believable curves that maintain the illusion of a solid, three dimensional form. Looking at this very curvy mercedes bus for instance shows a lot of very vague curves that in turn undermine the solidity of the form.

While you did employ a fair bit of subdivision, it really could have been pushed much farther.

Another thing to keep in mind is that there are a lot of areas where you realized that some part of your construction wasn't going to work - like in the VW bus, you realized that the bumper around the front had to push outside of the main volume in which you were constructing. This happens because you didn't work through the successive stages of scaffolding - you jumped too far ahead into an overly complex structure, and in turn ended up having to undermine/contradict the earliest stages, something you should really be avoiding at all costs.

For example, if you look at the earlier phases of construction in my shelby mustang demo, you'll note that the majority of the linework on the page was subdivision/perspective lines. I was drawing through most of my forms, and focused on constructing the core bulk of the car. Compare this then to this corvette, there's a lot less construction and a lot more focus on drawing what you see.

Now, I'm very confident that you can do better than this. You're demonstrating a pretty strong grasp of 3D space, but alongside it, a bit of impatience. That shelby mustang construction took me at least two hours to draw - I'd expect something like that to take you much longer. Usually when students submit work that suggests an amount of impatience, I point them to LordNed's submission with this Mitsubishi Lancer, which by his own account took him upwards of 10 hours.

This lesson is the big boss, and so it's going to take you a very long time to complete. So, I'm going to assign you a few pages of revision below to take another swing.

For what it's worth, your last few drawings are definitely impressive, and are frankly much more in the right direction than your more mundane non-starwars ones. You approached these with a lot of core structure, and built the complex details on top of a sturdier frame. This is what I want you to do when drawing your cars.