Hello Haider4123, I'll be the teaching assistant handling your lesson 4 critique.

Starting with your organic forms you've done a pretty good job of sticking to the characteristics of simple sausages that are introduced here.

Your lines appear quite smooth and confident, though something to work on is shifting the degree of your contour curves, as they are looking quite similar throughout these pages.

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. You can also see a good example of how to vary your contour curves in this diagram showing the different ways in which our contour lines can change the way in which the sausage is perceived.

Moving on to your insect constructions you're demonstrating a strong understanding of how the forms you draw exist in 3D space, and are doing a good job of starting your constructions simple, and gradually building complexity piece by piece which helps them to feel solid.

I do have some points that should help you get more out of these constructional exercises in the future.

The first of these relates to differentiating between the actions we can take when interacting with a construction, which fall into two groups:

1 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.

2 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.

For example, I've marked on your ant in red where it looks like you cut back inside the silhouette of the form you had already established for the thorax. I did notice that many of the more modest instances of cutting inside forms across your various constructions came down to the fact that your ellipses would come out a little loose (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.

On the same image I marked in blue where you'd extended off the existing form of the head using a partial, flat shape, not quite providing enough information for us to understand how this actually connects to the existing structure in 3D space.

Finally I popped a little note, if your construction won't fit on the page (which is fine) it helps to maintain the 3D illusion if you "cap off" the form, in this case with an ellipse, rather than running lines off the page, which leaves the form open-ended and tends to flatten it out.

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 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 is great to see that you've made an effort to stick with the sausage method of leg construction throughout the set. It's not uncommon for students to be aware of the sausage method as introduced here, but to decide that the legs they're looking at don't actually seem to look like a chain of sausages, so they use some other strategy.

The key to keep in mind here is that the sausage method is not about capturing the legs precisely as they are - it is about laying in a base structure or armature that captures both the solidity and the gestural flow of a limb in equal measure, where the majority of other techniques lean too far to one side, either looking solid and stiff or gestural but flat. Once in place, we can then build on top of this base structure with more additional forms as shown in these examples here, here, and in this ant leg demo and also here on this dog leg demo as this method should be used throughout lesson 5 too.

You've done a good job of sticking with sausage forms, and I can see some places where you've explored building on top of your base armatures with additional forms, this is all good stuff. Be aware of the placement of the contour curves noted in the sausage method diagram, these are used at the joints, and represent the intersections where these sausage forms connect together in 3D space. You don't need to add any additional contour curves on the surface of a single sausage form, only at the joints. You have this correct on quite a few pages, but there are cases like this dragonfly where contour curves appear to have been placed on the surface of the uppermost sausage forms, rather than at the joints.

I noticed a couple of places that use heavier line weight/cast shadows in ways that suggested you weren't necessarily distinguishing between the two. While they're similar in some ways, line weight and cast shadows have to adhere to different rules. Line weight can cling to the silhouette of a form, but has to remain very subtle and light, rather than getting super heavy and dark. It relies on relative changes in thickness that one's subconscious will notice. It's like whispering, rather than shouting. Cast shadows on the other hand do not cling to the silhouette of a form, and instead are cast onto a different surface. They can be much broader and heavier, but we can't have them floating arbitrarily in space without an actual surface to receive them. So if we take a look at the underside of the thorax on this beetle as an example, the line gets quite aggressively thick, but there is no other form present to cast a shadow onto the underside of the thorax here. What you're describing is a form shadow. I suggest you review this video where Uncomfortable explains the difference between form shadows and cast shadows.

I find that the most effective use of line weight - at least given the bounds and limitations of this course - is to use line weight specifically to clarify how different forms overlap one another, by limiting it to the localised areas where those overlaps occur. You can read more about this here. What this keeps us from doing is putting line weight in more random places, and worse, attempting to correct or hide mistakes behind line weight.

Conclusion

Overall your work is coming along well. I've called out a few things to work on, but they can all continue to be addressed into the next lesson, so I'll go ahead and mark this one as complete. Just be sure to actively tackle these points as you handle your animals. It's not uncommon for students to acknowledge these points here, but forget about them once they move on, resulting in me having to repeat it in the next critique (which we certainly want to avoid).