Jumping right in with your form intersections, you're doing a good job with drawing the intersections themselves - both with flat-on-flat, flat-on-curved and the especially tricky curve-on-curve intersections are demonstrating a strong, well developing grasp of how these forms relate to one another in 3D space. That said, there are two things I should stress:

• Generally speaking we only draw the visible side of the intersection. In your case the intersections themselves are really confidently drawn, so I'm less worried about it - but in general it just helps to focus on the visible section to simplify what can definitely become a very visually confusing situation compounding on top of a confusing spatial problem.

• More importantly however, stay away from those exaggeratedly stretched forms as explained here - try to stick to forms that are roughly equilateral in size instead.

Continuing onto the object constructions, the thing about this lesson, and what really makes it as challenging as it is, is that it's the first major taste of precision that a student encounters throughout this course. Precision is often conflated with accuracy, but they're actually two different things (at least insofar as I use the terms here). Where accuracy speaks to how close you were to executing the mark you intended to, precision actually has nothing to do with putting the mark down on the page. It's about the steps you take beforehand to declare those intentions.

So for example, if we look at the ghosting method, when going through the planning phase of a straight line, we can place a start/end point down. This increases the precision of our drawing, by declaring what we intend to do. From there the mark may miss those points, or it may nail them, it may overshoot, or whatever else - but prior to any of that, we have declared our intent, explaining our thought process, and in so doing, ensuring that we ourselves are acting on that clearly defined intent, rather than just putting marks down and then figuring things out as we go.

In our constructions here, we build up precision primarily through the use of the subdivisions. These allow us to meaningfully study the proportions of our intended object in two dimensions with an orthographic study, then apply those same proportions to the object in three dimensions.

Now, as far as this lesson goes, it's very normal to see students still rely on eyeballing things, at least past a certain threshold. So for example, a student might break things into halves, then quarters, and then kind of try to work based on that - this feature sits between these two subdivisions, so I'll try and eyeball that onto my 3D construction - but it leaves a lot of room for mistakes that isn't strictly required. That is more or less where your work is sitting currently.

For example, if we take a look at the orthographic study of your dumbbell, I've marked out here the major landmarks for the object itself with red lines, and the subdivisions you ended up with in blue. As you can see, they're not terribly congruent - but arguably it might be difficult to achieve subdivisions that actually line up with that without getting really granular - into the tenths and twentieths and more. But there is an alternative option.

As shown here, we can actually combine subdivision with mirroring. In red, I set up the two lines on the left (blocking out the main weights), then mirrored them across the center. Then, in blue, I did standard subdivision , breaking it into half for the big weight, then quarters for the smaller one.

This worked out pretty well for this object, and objects do in general maintain somewhat friendly proportions like this (just as a factor of product design), but if it was a little off, that's not really a big deal. What's most important is that the information we're transferring from the orthographic study to the construction is specific and clearly determined. No approximation, no eyeballing.

The other thing I wanted to call out is in regards to handling curves in our constructions. As explained here, curves are in their nature very vague and don't really provide a strong foundation for solid construction. And so, it's important to start out our constructions first with a focus on flat surfaces and straight edges, breaking our complex curves into a chain of these to define their spatial characteristics more firmly before rounding out those corners at the end.

In terms of additional examples of this, this mug is the most appropriate one I've got. The body of the mug (which is a cylinder) isn't an issue - it's a primitive with circular ends represented by ellipses, so it's actually fine in terms of specificity and solidity. It's the handle, however, that requires a little more doing. Note how we build it out first in blocks, and then only at the end do we smooth it all out.

So with that, I am going to ask for some revisions - or rather, just one. You'll find it assigned below.