All things considered, your scans look fine to me, and they don't appear too contrasty - though taking photos with a phone is frankly always going to be a better option if it's available.

Before I get into the critique itself, I'll address the two issues you pointed out:

• On the topic of cast shadows, it's something we improve with as our overall understanding of 3D forms and the way they relate to one another in 3D space improves. That's the primary focus of this course, so it is something that will improve - but you should absolutely not avoid something specifically because it's difficult, or doesn't turn out well. I don't force students to explore cast shadows in their drawings, but your response to having difficulty with something should generally be to explore it more, rather than less. The whole focus on "hurting" or "helping" your drawings isn't actually relevant - the drawings don't matter. They are, each of them, exercises, and so their only value is in what you gain from producing them, not what you have at the end. Now, the thing to remember is that a cast shadow defines a relationship. It is not something that is invented... at least not really. You do have certain control over it, choosing where you place your light source to keep those shadows consistent, but the key thing to remember is that the cast shadow defines the relationship between the form casting it, and the surface receiving it. You need to understand the nature of both of these elements, and how they sit in space, in order to effectively capture the shadow being cast. All the constructional drawings we do from lesson 3-7 are themselves just exercises in spatial reasoning - so as I mentioned before, that's something that will improve with practice. Just don't run from it.

• The main point to keep in mind with the cross-sectional slices of cylinders is that the ellipses that represent them must shift in their degree to establish how that cross-section is oriented in space relative to the viewer. I can see some of this in your work, although there are plenty of cases where you're maintaining the same degree (which would help explain why this is a point of contention for you). The best explanation I have currently for why the degree shifts is in the most current update of the lesson 1 ellipses video. There I explain it using some props and diagrams, so give it a look if you haven't already.

Anyway, onto your critique. Starting with your arrows, these are coming along fairly well. You're drawing the marks themselves with a fair bit of confidence to help push the sense that the arrows are moving through the world in a fluid manner - though this is definitely something that can be improved by pushing the confident execution further. There is some minor hesitation that stiffens the linework a little, so keep an eye on that and always remember that the ghosting method exists purely to allow you to do all your preparation beforehand, then execute in a more confident, care-free manner to nail down that sense of fluidity.

I strongly feel that you already improve on this front as you move into your leaves. The lines flow better - that is, those from the first two steps (the flow line and the basic leaf footprint), achieving a stronger sense of both how the leaves sit in space statically, and how they move through the space they occupy.

That said, when you start building on top of that structure, adding more complex edge detail, you do tend to hesitate more, and also in some cases (like this monstera leaf you basically end up trying to redraw the entire leaf within the framework of that simple silhouette. Constructional drawing is all about taking a complicated problem and breaking it down into simple steps that can be solved one at a time. It's not about redrawing the entire thing in successive phases, but rather only adding the parts that change from one step to another, as shown in this demonstration of a similar leaf.

This one also has a couple issues. Firstly, this is a complex leaf structure that should be broken down into several separate leaf structures (as explained here). You do have another complex leaf structure on the page that handled this much better. Additionally, you appear to be zigzagging your more complex edge detail, as explained here, instead of building it up bit by bit with separate additions that rise off the simpler edge and return to it.

As far as more complex leaf structures go, I also have this demonstration from the informal demos page which shows how to approach a similar structure with several "arms".

Continuing onto your branches, aside from the point about the ellipses' degrees that I addressed earlier, the main issue I'm seeing here is simply that you're not extending your segments fully halfway to the next ellipse as mentioned in the instructions. As a result, you end up with a minimal overlap between them. The overlap, [as explained here](), is a critical tool for achieving a smoother, more seamless transition from one segment to the next.

I also recommend that, at least for now, you try drawing these branches bigger, so you can engage your whole arm more easily when drawing those marks. It tends to be easier to handle these spatial problems when drawing big, because it both removes certain obstacles from engaging our whole arm (really just makes it easier to do so), and also helps engage our brain's spatial reasoning skills.

This point about drawing larger is an important one, as we move into your plant constructions. One thing that jumps out at me immediately here is that you're not making particularly good use of the space on the page. While the drawings themselves are generally probably large enough that you're engaging your whole arm and that it's not limiting your brain's spatial reasoning skills, you are however leaving a lot of empty space that could be taken advantage of.

When drawing throughout this course, the first priority is to give whatever object you're drawing as much room as it needs. Once that's done, you can assess whether there is enough room available to add another drawing. If there is, you certainly should add it. Otherwise, it is still okay to leave a single drawing on the page - as long as you've made good use of the page itself, and not for any other reason. To a similar point, there may be some plant reference images you choose to study that feature a lot of the same elements being repeated - for example, branches containing many instances of the same kind of flower. Rather than focusing on reproducing the reference image as a whole (which is not a focus of this exercise), it can be more beneficial to focus in on a grouping of a few of the more significant elements, and cutting out the rest, to allow yourself more space to explore them more fully. The lily of tha valley is a good example of this, where trying to draw the whole thing resulted in a lot of wasted space on the page, and made the individual flowers themselves quite a bit smaller.

Looking through your work, another point that stands out, is one that I've already addressed - you need to be using the ghosting method for all your linework to ensure that it comes out smooth and confident. Right now, there's a lot of hesitation that results in wobbly lines and uneven ellipses. Doing so will also help you more purposefully execute your lines from your shoulder, using that whole arm to further emphasize the flow of your marks rather than their accuracy. The aloe plant is a good example where your linework was quite hesitant, and it undermined the solidity of the forms you were constructing.

One last thing I want to mention is that it may be better for you to try your drawings without the extensive use of large "enclosing" forms (like how you enclosed the individual plants in this drawing in cylinders). This kind of approach does have its place - like where we use an ellipse in the hibiscus demo to establish the specific perimeter to which all of the petals extend - but it should be used sparingly. Like in the hibiscus drawing, those structures aren't loose containers or approximations - when in place, they define a clear answer for how far certain elements will extend. So, alternatively, in the daisy demo drawing, I didn't include this approach because I knew my petals would extend to different distances.

To that same point, don't draw any part of your constructions more faintly than anything else, as you did here. Towards the end you can have a pass to add line weight to specific localized areas that need the overlaps between forms clarified, or to add specific cast shadows, but you should not be modulating that throughout the main construction process. Keep those lines roughly similar in line weight and don't go out of your way to draw anything more faintly in order to hide them or make them less relevant to your construction.

As a whole you are moving in the right direction (and honestly I have no issues with how your cast shadows are coming along), but I think that your concern about these points are perhaps keeping you from putting enough attention towards some of the more basic elements - like the execution of your linework. I'm going to assign some additional pages of revisions below so you can address this. Remember most of all - your only responsibility here is to apply all of the steps, techniques, and processes to the absolute best of your current ability. Don't worry about anything else, because any other concerns will distract you from this basic responsibility.