Hello drvanger, 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, and you’re drawing the forms with smooth confident lines, which is great.

You’re also doing well with experimenting with shifting the degree of your contour curves, which is an aspect of this exercise that students often overlook, well done.

You’re getting a mixture of some contour curves which are very smooth, and some which are a little bit stiff or uneven. Something that might help with these contour curves, is to try ghosting the whole ellipse, and just place the pen down for the section of the ellipse that forms the contour curve, I found that helped to reduce the number that came out stiff or lopsided.

Moving on to your insect constructions, you’re doing an excellent job. Your linework continues to be smooth and purposeful, and you’re making great use of the methods shown in the demos for this lesson.

You’re starting your constructions with simple solid forms and gradually building up complexity by attaching new forms to the existing structure, establishing specific relationships between the various pieces that allow the viewer to understand how construction sits in 3D space.

You’re doing very well at taking actions on your constructions “in 3D” but I’m still going to share a piece of pre-written text with you that will help clarify why your approach is correct, and provide some additional information that I’ve been passing to students who are on the official critique track as a “free preview of future concepts.”

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 an example of what happens when we try to cut back inside or extend off and existing form by altering its silhouette in this diagram showing the various kinds of actions we can take on a sphere. When engaging with organic constructions in this course we’d like students to stick to “addition in 3D” as shown in the lower right. Fortunately you’re already doing this throughout almost all of your constructions.

I did spot a couple of places where it looks like you’d either extended off an existing form with a partial shape, or completely replaced a form by enclosing it within another. I’ve marked one example of what I mean with blue on this spider. Here you’d added to the basic ball form using the blue shape, but it is a little ambiguous how the addition connects to the surface of the ball in 3D space. I can clearly see that you are thinking about how this form sits in space from the contour lines you’ve added, but these don’t necessarily help define the connection between the ball form and the addition. As shown here, instead of adding contours running across the surface of a single form (as they were introduced in the organic forms with contours exercise) we can define a clear relationship between the ball and the addition, by running the contour across the surface of the ball where the additional form connects to it (like from the form intersections exercise). Establishing how the pieces fit together like this is a very effective tool for reinforcing the solidity of the construction as a whole, and is the reason behind applying a contour line to each joint when using the sausage method of leg construction.

So, 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’re already applying this well throughout the set, but in case it may be helpful, I’ll go ahead and share a couple of examples of this in practice with 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. You’ve clearly made an effort to stick with the sausage method of leg construction and are applying it well.

I do have some advice to offer on how to build onto those sausage armatures to develop the construction into a more characteristic representation of the leg in question.

In general, try to avoid entirely engulfing an existing structure in the new element you add, as seen along the limbs of this mantis. This can limit how much actual contact the new mass’ silhouette has with the existing structure, and therefore defines a weaker relationship with it. Instead, we can break apart the new mass into separate pieces as shown here, defining each one's relationship individually, and ultimately yielding a stronger, more solid result.

Generally we’ll want to avoid having additional forms running long distances along the length of a leg. Running lengthwise in this manner gives us a more limited opportunity to really "wrap" the new masses around the existing sausage. Instead, if we twist those new masses around the existing structure, as shown in this ant leg demo we can focus much more on how the silhouette of the new mass interacts with the existing structure. Here we can actually design that silhouette, rather than just stamping down a flat shape on the drawing. This principle can be applied to all situations where we build upon an underlying structure to add more nuance and specificity to its structure, as shown here.

Before I wrap this up I’d like to share this dog leg demo which shows an example of how to apply the sausage method to animal constructions. Please continue to stick with the sausage method of leg construction throughout lesson 5.

All right, your constructions are coming along very well and I’ll go ahead and mark this lesson as complete.