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

Starting with your organic forms most of these are fairly close to the characteristics of simple sausages that are introduced here. There's the occasional form with one end larger than the other, or some pinching or bulging through the middle, so keep working in sticking to those simple characteristics consistently, with each form.

Most of your contour curves appear to be sticking to a similar degree. 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 these are coming together very well. You're doing a good job of starting your constructions with simple solid forms, and then building up complexity gradually, without attempting to add more complexity than can be supported by the existing structures at any given stage. You're showing that your spatial reasoning skills are developing as some of your constructions demonstrates that you're thinking about how your forms fit together in 3D space, and not just as flat shapes on a piece of paper.

You're doing a good job, and I have just a couple of points to discuss that should help you to get even 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:

• 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 the silhouette of forms you have already drawn very much at all, and the only places where I saw this happen 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. I've highlighted one such instance in red on your spider. 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 green where you'd done a fantastic job of building onto the head using a 3D form, and in blue and example where you'd extended off the existing form of the abdomen using a partial shape, not quite providing enough information for us to understand how it actually connects to the existing structure in 3D space.

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 looks like you've made an effort to stick to the sausage method of leg construction, and you're generally applying it quite well. I noticed sometimes you'll add extra contour lines to the surface of individual sausage forms, but by using a contour line at each joint to define how the forms intersect (which I'm happy to see you usually remember) we actually make the use of additional contour curves on the surface of individual sausage forms somewhat obsolete.

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. I'm happy to see that you're exploring this idea and building onto many of your leg structures with additional forms.

While it seems obvious to take a bigger form and use it to envelop a section of the existing structure, (as seen on this treehopper) it actually works better to break it into smaller pieces that can each have their own individual relationship with the underlying sausages defined, as shown here. The key is not to engulf an entire form all the way around - always provide somewhere that the form's silhouette is making contact with the structure, so you can define how that contact is made.

We can see this approach being pushed further to capture the various kinds of lumps, bumps and complexity we see in these sorts of structures in this ant leg demo and also here on this dog leg demo as this method should be used throughout lesson 5 too.

The last thing I wanted to mention is that sometimes you'll add lineweight to places that seem somewhat arbitrary, such as all along the top of the treehopper. Tracing back over large sections of the silhouette to add line weight like this tends to switch a student's focus from thinking in 3D and drawing complete forms, back to drawing individual lines on the flat surface of the page. It also has a tendency to cause students to neglect the principles of markmaking, as it encourages drawing scratchy or wobbly lines from the wrist. Instead, the most effective way to use additional line weight in this course is to reserve it for clarifying overlaps between forms, and restricting it to localised areas where those overlaps occur. You'll find instructions for how to use line weight in this course in this video which was added to lesson 1 a couple of months ago.

Okay, I think that should cover it. Your constructions are working well and I'll be marking this lesson as complete. Please refer to the advice in this critique as you tackle the next lesson, the diagrams and demos I've shared here will be applicable to building animal constructions.