No problem, and I'm also sorry to hear you felt a bit underwhelmed by some of the sections here. Hopefully some of the explanations I provide here can help with that. I also apologize in advance as I will probably ramble a bit throughout this.

While it may not fully rectify your feelings I'll explain why I choose to focus on some of the sections more than others, then talk about form intersections, and then wrap this up with a lengthy texture explanation that I give to students who ask for more clarification on texture (it's a complex topic and honestly is comparable in length to the critique I gave you, I generally don't include it in the critiques themselves because it can cause students to focus on it, feeling it's much more important than it is currently).

To begin with a brief explanation of how the course material is structured is so that Lesson 1 gives you some of your extremely basic fundamentals and tools. The box challenges builds up your mileage with those tools so that they're a bit more consistent and gets you thinking about 3D space (what this entire course is about). Then lesson 2 introduces and gives you some of the more difficult fundamentals and tools that you'll be expected to use going forward.

After this point is when you start applying those fundamentals to real life objects and forms rather than just primitive shapes (cubes, spheres etc.), because of this there is a bit of a trade in difficulty that occurs. On one hand you know what these objects are meant to look like so if you see a leg connecting to a body incorrectly (like in lesson 5 where you'll be drawing animals), it's easier to identify if something is incorrect compared to a few nebulous forms that you need to create in 3D space. On the other hand this becomes much less forgiving and there's less room to make excuses if something is incorrect (If I point out that an intersection between 2 boxes implies that a box is behind a different box, you can argue that that's intentional and I can't really argue it as I have no way to tell if you really meant for those boxes to interact in that particular way. If your drawing of a dog's leg implies that the leg is inside of the dog though you can't talk your way out of it). It's also much more intimidating for some to tackle these real life challenges because their inner critic is so quick to latch on to something being incorrect.

Now what I've described plays a factor in which sections I put more focus into. Arrows, and organic forms are very useful in terms of getting you to think more organic-shaped forms would exist in 3D space and are useful building blocks in a lot of the challenges coming up. Remember that this lesson is still largely about just introducing you to your tools that you'll be expected to use, the reasons I don't stress as much about students understanding texture and form intersections is that they're very difficult and that either they really aren't as important right this second, (referring specifically to texture here, if you can create strong believable forms in 3D space then your illustration will be solid, texture is detail and it's the last 10% of the process, it does take a long time and it does need to be worked on of course but everything else introduced up to this point is much more critical at this moment in time.) and that while things could be better explained at times (texture is another culprit here among others that we're working on) a lot of a person's understanding of these concepts comes from mileage more than anything.

You need to know that this idea exists so you're consciously thinking about it but from that point a lot of it comes down to experimenting with different scenarios and building up mileage until the switch in your brain toggles and suddenly it clicks (this is prevalent in other creative hobbies as well, guitar being one of them where barre chords give people a ton of trouble until suddenly people can play them and have no clue what they're doing differently). While it may feel pointless and like you're doomed to fail, if we just explained it and you didn't have to even attempt it most people wouldn't retain these ideas and just move on to the next step. Now this can be underwhelming feeling and some people feel they need to understand things completely before they tackle them and I do understand that feeling as I've felt similarly in the past. I need to stress however what I've mentioned before where you will be using these concepts and tools going forward and in ways that you'll be able to more clearly identify when you're doing them correctly or not. Everything you draw from plants, insects, other animals, everyday objects, vehicles and people are going to be composed of multiple forms intersecting, you'll be building up that experience and mileage whether you want to or not and given enough time it will click.

In the form intersections itself all I'm looking for is that you attempted to draw any intersections at all and then for a few other factors like are your forms looking solid or are they rushed (when faced with drawing a page full of forms some students begin to get lazy, overwhelmed or just feel like they're going too slowly and end up rushing this process). Are you sticking to the principles of markmaking, are your lines converging or are they diverging, basically it's a check up on every concept introduced up until this point. Other than that it's just meant to introduce the concept of intersections and any time that I spend nitpicking individual intersections isn't the best use of time for anyone, it means that I have to figure out how to point to those specific attempts, (and potentially draw over your attempts if it can't be described easily which eats up a ton of time) and then describe the issue at which point you can argue that it's not what you intended. Or I can realize that this is likely your first (or at least something you're likely not super familiar with) attempt at tackling this sort of thing and that you're going to improve and grow rapidly once you're faced with forms you're more familiar with in terms of 3D space and encourage you to keep moving forward. While there are times where I have no issue going more in-depth, (like when people ask for further clarification) often the fastest way to help the person improve with these particular concepts is to just keep them working forward and not creating roadblocks needlessly. You don't fully grasp something, you aren't expected to, trust the process and you'll improve as long as you follow the instructions like everyone else who continues to progress, experiment and build up mileage.

If however the above explanation isn't satisfactory enough I'll quickly point out that the intersections you've drawn on your boxes are off to a good start and headed in the right direction. You struggle more with intersecting spheres, cones, cylinders etc. Again this all makes total sense and is expected, this is the first time in the course you've worked with these forms and on top of that you're dealing with a brand new difficult concept. All I want to see is that you're trying and that you're thinking, and you've done that.

I'm going to quickly go over texture and then wrap up your explanations here and then include my more lengthy texture explanation below, partly because I've been writing for over an hour at this point and my hands are getting fatigued and partly for organization so you have clearer breaks between some of the form intersection reasoning and the texture explanation. Seeing as this is quite lengthy having the split will make it easier (I hope at least) to revisit if you feel the need to do so.

While the texture video you've provided may be incredibly knowledgeable and helpful it won't be tackling texture the way this course intends. While there isn't one specific way to do things of course, just know that the way texture is tackled in this course is meant specifically to help with your understanding of 3D space and we aren't able to deal with multiple values by utilizing hatching or different shades (again not that this is wrong just not the point here). Instead we have 2 values to choose from, black or white, shadow or no shadow.

In your reply you mention:

A lot of specific examples given in the demos, are very blatantly inaccurate to the shadow shapes from the images, yet look very convincing on paper. How come?

While there may be errors and Uncomfortable is also more experienced so he may be noticing things you don't see there's also just an explanation in what this exercise is meant to tackle. You're not attempting to recreate the texture 1 to 1, you're not trying to capture every single detail possible. The goal is as it's described in the reminders section here. You're meant to observe, understand, and then transfer your understanding to the page. The difference may not be obvious at first (or in the explanation itself potentially) but what you're asked to do is look at your reference, think about how the forms along the texture exist in 3D space, (do forms raise, do they lower, what shape are they etc.) then think about where you've placed your light source. From that point it becomes a matter of personal decision making and picking what best suits your illustration, at which point you are tasked with creating cast shadows based on those forms and choosing which to include to best imply the existence of those forms. Sometimes this means you ignore a form because it would create too busy of an image, sometimes it means you need to create or merge shadows to create the implied information you need. It's not about explicitly drawing every little detail but instead creating enough cast shadows to give the impression of forms existing implicitly.

I'm hopeful that I do a better job of going more in-depth in the explanation below so I'll be directing you that way after wrapping this up.

Again I hope that this can help alleviate some of your feelings of being underwhelmed and can help get rid of at least some of the worry about potentially not understanding things just yet. Learning anything is hard and it's understandable that people want to feel like they're in control and have as much understanding as possible, all I can ask is that you trust the process. While there may be mistakes in some of the course material we are working on correcting it as we can, and do our best to help students when/if those issues present themselves in their work and try our best to address any questions they may have.

As a side note, it's worth noting that the form intersections and texture material isn't actually as different or distinct as it may seem. At the end of the day, they both rely on understanding different kinds of spatial relationships between forms in 3D space. Because of this, just like the form intersections will improve as we work through the constructions we'll encounter through lessons 3-5, so too will the understanding of the spatial relationships involved in the textures we draw.

If after all of this you're still left unsatisfied and feel things haven't been addressed well enough feel free to reply and either I or Uncomfortable will try to tackle it (though again, part of learning is trusting the process so all I can ask is that you try to do so the best you can).

Apologies again for all the rambling, if I don't hear back from you I wish you the best of luck with lesson 3 and the rest of the course. I'm off to run my hands under cold water for a while.

Texture Explanation

Rather than being able to give you just one or two pointers about things to work on, texture is often a case of people trying to simplify the steps too much and it's easier for me to just explain the entire process.

First things first, open up this leaf texture picture, I find leaves are a good example and a texture that people are often drawn to and do incorrectly.

The first thing you may notice is that this image isn't in colour and instead in black and white, this is helpful because people often get distracted by shifts in colour and will try to darken an area in their drawing if the colour happens to be darker. We shouldn't rely on converting images to black and white but it is helpful and something you may want to consider when practicing.

Now if I handed a student this image and told them to use it for their texture exercises there are two typical outcomes I would expect.

The first is that they would draw all of the veins (or many of them if they aren't extremely patient), and this would be an example of focusing on outlines.

The second result that I would expect is that instead of drawing the veins themselves they would either fill the veins in completely with black or they would fill in everything but the veins completely with ink, and this would be them focusing on negative space.

This is where students get a bit confused at the start, they feel like they're looking at the image and drawing what they see but it comes out wrong. I should clarify that it's not necessarily incorrect, there is a time and place when obsessing over small details can be helpful but this is largely an exercise about learning how to imply information and thinking in 3D space. Remember that what we're learning here isn't observational drawing, it's constructional and while observation is definitely a part of the construction method there's an extra step that people tend to neglect in the beginning.

With that in mind let's go over the correct way to tackle these problems, bring up the leaf image (it's here if you closed it) and let's break down what we're working with. What people tend to neglect is that we're trying to think about the 3D space of the image we're observing and drawing. If we look at this leaf the veins are really just long organic forms, or cylinders if they're particularly rigid. The fleshy bit of the leaf could be thought of as either a plane or a thin box, and due to gravity's effect it will likely curve a bit (we don't need to think too much about it curving in this case because we're working so close up, but it's good to think of how the environment can have an effect).

To put it simply, a leaf is just organic forms that are intersecting with each other and a plane/box, just like the forms we practiced with in the form intersections exercise. With all of these forms in mind we can place a light source and depending on it's position and intensity we can create cast shadows much like we did in the organic intersections exercise.

An example of this can actually be seen in the picture itself. Let's just focus on the large main vein as well as the branching vein on the left. You'll notice that if you look along the bottom edge of the main vein there's a cast shadow, and on the right of the branching vein there's a shadow. From this information we can assume that the light affecting the leaf the most is somewhere to the upper left of the image and it's creating the cast shadows we want to draw.

This is an example of what drawing cast shadows might look like, it comes up early on in lesson 3 when Uncomfortable shows the process of drawing a leaf. You can see that he's not actually drawing the veins themselves, and instead just implying that they exist by creating cast shadows. Keep in mind that this leaf is fairly evenly lit and the point of the texture exercise is to work with light gradients but regardless it's a good example of what we're trying to achieve. There are times where capturing shadows doesn't immediately give the impression of what you're attempting to draw but it's just a single tool that you can use. You may not think that drawn leaf looks like a leaf, but if it was green, had a stem, and was attached to something that resembled a plant your brain would begin fill in the gaps until it goes "oh that's a leaf".

Implying information helps both the creator as well as the viewer, it saves the creator time from having to obsessively capture every tiny detail and it prevents the image from becoming too visually noisy and overwhelming for the viewer.

Craig Mullins is a painter whose work I appreciate a lot and I feel does an amazing job of implying information through shadow, colour and brush strokes. I highly recommend looking up some of his work if you'd like some examples of just how powerful implied information can be.