Starting with your form intersections, your work here is looking pretty solid for the most part. Your forms feel consistent within the same space, and the intersections themselves demonstrate an overall strong grasp of how the forms relate to one another in space, although I did catch one little hiccup - here in this sphere/cone intersection, you've got the intersection line curving in the wrong direction. Remember that we want to be running along the surface of both forms simultaneously, so that would require a curve in the opposite direction so that it continues to follow the surface of the sphere. This is by no means a big concern though - the odd mistake is pretty normal, and it could very well be a matter of having put down the wrong mark, realized it, but opting not to correct it, which is the right course of action.

Glancing at your cylinders in boxes, your work here is coming along well - line extensions are applied correctly, and you're demonstrating that you're continuing to apply the exercise correctly.

Continuing onto your form intersection vehicles, I should mention that while your work here is good, you actually went beyond what was intended - the exercise is really just the form intersections, but with the forms laid out in a particular fashion, to match a given vehicle. No need to pin down the specific proportions using the "measuring to scale" technique. That's more for the later vehicle constructions, when we get into much more constructed detail.

That said, you did fine on that - you still stuck to the primitive forms within the framework of your proportional bounding boxes, and where you did go beyond that, I'm pleased to see that you worked your way to more refined details in a step by step manner, avoiding making large leaps of logic and relying too much on the spatial reasoning skills that we're looking to develop.

Moving onto your more detailed vehicle constructions, overall you've done a similarly solid job here, and have been adequately patient and conscientious as you stepped through each phase of construction. I do however have a couple of things to call out that should help you as you move forwards.

The first of these is pretty minor, and only pertains to one construction - your helicopter. You built up the core construction of the helicopter very well, but ended up building the rotors inside of an ellipse with no preceding structure to help establish it in relation to the rest of the object. As a result, it did end up somewhat lopsided.

By and large your strategy here was pretty solid, but starting with a box or a plane would have been a better first step, as it would have been much easier to orient it relative to the main bounding box. Even if the degree/orientation of the ellipse you'd place inside of it were off from what would constitute an actual circle in 3D space, it wouldn't actually be super obvious to the viewer unless it was especially egregious - whereas the degree of the ellipse being off as it is here gives us a much clearer sign that what we're looking at is slanted unintentionally.

The second point I wanted to talk about is how you're using your filled areas of solid black. Keep in mind that for the drawings we do for this course, specifically due to the way in which we're limited to pure black and pure white for our marks and shapes, the filled areas of solid black are really best reserved for capturing specific cast shadows - that is, cases where the shape itself implies the relationship between different forms.

In your drawings, there are two main ways in which you've used these filled areas of solid black:

• Cases where you've filled in a side plane or other defined face of an existing form - which is more akin to form shading, which as discussed here should be left out of our drawings for this course.

• Cases where you've filled in windows completely.

When it comes to the windows, this can actually flatten out our constructions because it largely ignores what exists inside of the object and instead gives us the impression that we're actually painting the windows themselves matte black, and capturing that local colour in our construction. It results in a filled black shape that doesn't actually define or imply structures that exist in 3D space, in the way that cast shadows generally do.

But you're not far off. In fact, many of my demos use filled areas of solid black on the windows, but there's a distinction - what we're doing is casting a shadow from the outer structure of the vehicle, onto the internal surfaces. Where we're able to look through one window and out another, we leave it white, resulting in little silhouettes of those internal structures. For example, note the difference here that carving out even a basic (admittedly shoddy) silhouette of a chair makes for the cockpit of this train.

Now obviously your reference gives you no such interior information - but in that case, it would be preferable to leave the filled areas of solid black out altogether, because their purpose ends up being to capture the local surface colour of the tinted windows, rather than something that relates to the 3D relationships between the forms in our construction.

Anyway! All in all your work is very well done, and you're demonstrating solid use of the techniques and tools introduced throughout the course. I am confident that your spatial reasoning skills have been developed quite well, and that you have earned the right to claim completion not only of this lesson, but of the course as a whole.

Congratulations - this is no small feat that you've accomplished, and you should be proud of yourself.