Hello KHOAI, I'll be the teaching assistant handling your lesson 4 critique.

Starting with your organic forms most of these are sticking to the characteristics of simple sausages that are introduced here, and you’re doing a good job of drawing them with smooth confident lines.

When you’re deciding whether to place a small contour ellipse on the tip(s) of your forms, remember that these ellipses are no different from the contour curves, in that they're all just contour lines running along the surface of the form. It's just that when the tip faces the viewer, we can see all the way around the surface, resulting in a full ellipse rather than just a partial curve. But if the end is pointing away from us, there would be no ellipse at all. Take a look at this breakdown of the different ways in which our contour lines can change the way in which the sausage is perceived - note how the contour curves and the ellipses are always consistent, giving the same impression of which ends are facing towards the viewer and which are facing away.

You’re doing well at shifting the degree of your contour curves, which is an aspect of the exercise students often miss. I do have some advice about how the shift in degree will usually occur. Keep in mind that the degree of your contour lines should be shifting wider as we slide along the sausage form, moving farther away from the viewer. This is also influenced by the way in which the sausages themselves turn in space, but farther = wider is a good rule of thumb to follow. If you're unsure as to why that is, review the Lesson 1 ellipses video.

Moving on to your insect constructions I am very pleased to see that you are going whole-hog on additive construction, mindfully building up your insects through the addition of simple forms, achieving greater complexity through these means instead of simply drawing forms that are more complex from the get-go. I can see plenty of places where you're defining the relationships between those forms as they're built up as well.

Overall you’re doing a great job, and I have just a couple of things to discuss which I hope will help you get even more out of these constructional exercises in future.

The first point I want to talk about relates to differentiating between the actions we can take when interacting with a construction, which fall into two groups:

• Actions in 2D space, where we're just putting lines down on a page, without necessarily considering the specific nature of the relationships between the forms they're meant to represent and the forms that already exist in the scene.

• Actions in 3D space, where we're actually thinking about how each form we draw exists in 3D space, and how it relates to the existing 3D structures already present. We draw them in a manner that actually respects the 3D nature of what's already there, and even reinforces it.

You can see examples of the various kinds of actions we can take on a construction in this diagram using the context of a sphere. When working on organic constructions in this course we’d like you to strive to only take actions on your constructions by adding in 3D. You do generally do this well, although there are a few places where you’d taken a form you’d already drawn and attempted to alter its silhouette, flattening it out.

Fortunately you don’t cut back inside the silhouette of forms you have already drawn very much at all, and the only places where I saw this are most likely accidental. For example, on your crab I’ve marked a couple of spots where you’d chosen one of the inner lines of your ellipse to represent the silhouette of the body, leaving some stray lines floating outside the construction to remind the viewer that the drawing consists of lines on a flat piece of paper. Generally it is best to treat the outermost perimeter of the ellipse as the edge of the silhouette, so everything else remains contained within it. This diagram shows which lines to use on a loose ellipse.

On this weevil I marked in blue a couple of examples where you'd extended off existing forms using partial, flat shapes, not quite providing enough information for us to understand how they actually connect to the existing structure in 3D space.

Instead, when we want to build on our construction or alter something we add new 3D forms to the existing structure. Forms with their own complete silhouettes - and by establishing how those forms either connect or relate to what's already present in our 3D scene. We can do this either by defining the intersection between them with contour lines (like in lesson 2's form intersections exercise), or by wrapping the silhouette of the new form around the existing structure as shown here. Here is an example of how we could apply this to the weevil construction.

This is all part of understanding that everything we draw is 3D, and therefore needs to be treated as such in order for both you and the viewer to believe in that lie.

You can see this in practice in this beetle horn demo, as well as in this ant head demo. You can also see some good examples of this in the lobster and shrimp demos on the informal demos page. As Uncomfortable has been pushing this concept more recently, it hasn't been fully integrated into the lesson material yet (it will be when the overhaul reaches Lesson 4). Until then, those submitting for official critiques basically get a preview of what is to come.

The next thing I wanted to talk about is leg construction. It looks like most of your leg constructions are using the sausage method as introduced here, which is great. I spotted a couple of things which you can adjust to make more effective use of the method moving forward.

• Sometimes you draw around your leg forms twice. We ask students to draw around their ellipses two full times, because this leans into the arm’s natural tendency to make elliptical motions and helps to execute them smoothly. Sausage forms require a different series of motions to draw, so drawing around them twice isn’t helpful, and can lead to students accidentally making their sausage forms elliptical, stiffening the construction. Please only draw around your sausage forms once in future.

• There are a couple of constructions that appear to be missing some of the contour curves at the joints, which we use to define how the forms intersect. They are present in most cases, but it is worth mentioning that using contour lines to define how different forms connect to one another is a very useful tool (and one you use fairly well). It saves us from having to add other stand-alone contour lines along the length of individual forms, and reinforces the illusion of solidity very effectively.

It is great to see that you’ve taken a swing at building onto your sausage armatures on many of your pages, adding the sorts of lumps, bumps and complexity that you observe in these structures, arriving at a more characteristic representation of the leg in question than what can be achieved with the sausages alone. I have some diagrams to share with you that I hope will help you to build onto your leg structures “in 3D” as you move forwards.

• These diagrams show how we can add to the construction with complete 3D forms instead of flat shapes and one-off lines.

• This diagram shows how instead of fully engulfing an existing form within a new one, we can establish a clearer relationship between the existing form and the new addition by breaking it into two pieces.

• This ant leg demo shows how we can take the sausage method and push it further, adding all kinds of lumps bumps and spikes to the sausage armature.

• I’d also like to share this dog leg demo with you, which shows how the sausage method can be applied to animal legs. This is important, as we’d like you to continue to stick with the sausage method of leg construction when tackling your animals in the next lesson.

The last thing I wanted to mention is texture and detail. When adding texture to constructions in this course, try to approach it in the manner introduced in the texture section of lesson 2. By that I mean implying the small textural forms running along and object’s surface, by drawing the shadows that those small forms cast onto the surface. Think of it as though you’re trying to tell the viewer how the surface might feel to run your fingers over it. There are definitely places where you’re heading in the right direction, such as where you’d implied small bumps on the claws of this crab. We generally want to avoid filling in large areas with solid black, such as on this beetle. This doesn’t provide much information about the surface texture, and removes some information by obscuring parts of the underlying construction. If you are unsure how to approach texture for these exercises, these reminders are a good section to review.

Okay I think that should cover it. You’ve done well with this lesson and I think you’re ready for the challenges of lesson 5, so I will mark this as complete. Please keep the points discussed here in mind as you tackle the next lesson, they will continue to be applicable to animal constructions.