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

Starting with your organic forms you're doing a pretty good job of sticking to the characteristics of simple sausages that are introduced here. There are a couple of slight inconsistencies, such as an end that gets a little stretched out and pointy, but most of these are really close to those simple characteristics, good work.

You’re also doing well at keeping your linework smooth and confident, and I’m happy to see that you’re experimenting with shifting the degree of your contour curves.

I notice you often draw the small contour ellipses on the tips of the forms as circles, or at least with a very wide degree. 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. With this in mind, I’d generally expect the contour ellipse to have a fairly similar degree to the contour curve adjacent to it.

Moving on to your insect constructions you’re honestly doing an excellent job here, you’re sticking to the principles of markmaking, “drawing through” your forms and including parts that may be obscured in the reference image, and thinking through how your forms exist in 3D space connect together with specific relationships.

I only really have two points for you to keep in mind as you move forwards, which should help you to continue to get the most out of these constructional exercises as in future.

The first of these 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.

Because we're drawing on a flat piece of paper, we have a lot of freedom to make whatever marks we choose, but many of those marks would contradict the illusion you're trying to create and remind the viewer that they're just looking at a series of lines on a flat piece of paper. In order to avoid this and stick only to the marks that reinforce the illusion we're creating, we can force ourselves to adhere to certain rules as we build up our constructions. Rules that respect the solidity of our construction.

For example - once you've put a form down on the page, do not attempt to alter its silhouette. Its silhouette is just a shape on the page which represents the form we're drawing, but its connection to that form is entirely based on its current shape. If you change that shape, you won't alter the form it represents - you'll just break the connection, leaving yourself with a flat shape. We can see this most easily in this example of what happens when we cut back into the silhouette of a form.

Fortunately you don’t cut back inside forms you have already drawn very often. I did spot a couple of examples, which I've marked on your scorpion in red where it looks like you cut back inside the silhouette of forms you had already drawn. This can happen accidentally in places such as the claw, when there is a gap between passes around an ellipse (which is totally normal), and then you'd pick one of the inner edges to serve as the silhouette of the ball form you were constructing. This unfortunately would leave some stray marks outside of its silhouette, which does create some visual issues. 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.

It is also possible to alter the silhouette of a form we have already drawn by extending it with flat shapes, not quite providing enough information for us to understand how they actually connect to the existing structure in 3D space. I have marked a few examples in blue on this beetle.

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.

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 you made a determined effort to use the sausage method of leg construction on most of your pages. Keep in mind that when you apply the contour lines at the joints that these are the type of contour line that shows how these sausage forms intersect and connect together in 3D space, much like how we added contour lines to define the intersections in the form intersections exercise. This type of contour line can only exist where both forms are present, which is represented on the page by the area where the forms overlap.

I’m happy 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.

Okay, that should cover it. You’re doing a great job and I’ll be marking this lesson as complete.