Lesson 4: Applying Construction to Insects and Arachnids

6:33 PM, Tuesday April 4th 2023

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Also, how does one figure out how to make a believable drop shadow?

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10:37 AM, Wednesday April 19th 2023

Hello Tygerson, I'll be handling your lesson 4 critique.

Starting with your organic forms you're doing a good job of sticking to the characteristics of simple sausages that are introduced here. Sometimes a form has one end larger than the other, like this, try to keep them evenly sized in future.

Your contour curves are well aligned, and most of them are really smooth and confidently executed, nice work.

You appear to be drawing the majority of your contour curves with 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 it's clear that you put a lot of thought into how to build your constructions piece by piece, and you're demonstrating an understanding for how the forms you draw exist in 3D space.

You're doing well but 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 work here in red where you cut back inside the silhouette of forms you had already drawn. Sometimes I think you accidentally cut inside forms you have already drawn where there is a gap between passes on your ellipses. There is a way we can work with a loose ellipse and still build a solid construction. What you need to do if there is a gap between passes of your ellipse is to use the outer line as the foundation for your construction. Treat the outermost perimeter as though it is the silhouette's edge - doesn't matter if that particular line tucks back in and another one goes on to define that outermost perimeter - as long as we treat that outer perimeter as the silhouette's edge, all of the loose additional lines remain contained within the silhouette rather than existing as stray lines to undermine the 3D illusion. This diagram shows which lines to use on a loose ellipse.

On the same image I marked in blue where you attempted to extend your silhouette without really providing enough information for us to understand how those new additions were meant to exist in 3D space. For the legs, this really highlights the importance of "drawing through" and completing your forms by including the parts you can't see. Imagine you are drawing these constructions like you have X-Ray vision, don't cut your forms off where they get obscured by something else in your reference. For the antennae, a single line is infinitely thin, and doesn't really provide enough information to convey form. I'd suggest using either the branch construction from lesson 3, or sausage forms. This may result in something chunkier than you see in the reference, but remember our goal isn't necessarily to reproduce the reference image at all costs, but rather we treat is as a source of information. What matters most of all is that you hold to the 3D structure you're building up, and that you do not undermine its solidity under any circumstances. If that means the end result not matching up perfectly in some ways with your reference, that's fine.

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.

I'm noticing a tendency to start your construction off lighter, and then increase the weight of your marks as you progress. This can encourage us to redraw more of the structure than we strictly need to. I would strongly recommend that you maintain roughly the same thickness of line throughout the entire construction, applying further line weight for clarifying overlaps only towards the end.

The next thing I wanted to talk about is leg construction. It's good to see that you’re using the sausage method of leg construction on most of your pages. 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.

So, I can see you're working on using the sausage method, and I have a couple of notes that should help you take these constructions to the next level as you move forward.

  • The above point about altering the silhouette of forms you have already drawn applies to leg constructions too. Try to avoid altering your legs with single lines or partial shapes.

  • There are a couple of pages where you'd added a few extra contour curves along the length of your sausage forms. Here is an example. This is noted on the sausage method diagram as something to avoid, they tend to stiffen the construction.

  • Instead, we apply a contour curve for the intersection where the sausage forms join together, as highlighted in red on this coy of the sausage method diagram I can see you've included these on a few of your legs, but not very consistently. These little curves might seem insignificant but they do a great deal to explain how the sausage forms connect together in 3D space, so be sure to remember to include them in future.

Alrighty, you're doing a great job with this lesson. I've given you some things to work on, but they can all be applied to animal constructions so I'll go ahead and mark this as complete. Please refer to this critique as you work through lesson 5, the various diagrams and demos I've shared here should help you tackle your animal constructions. Best of luck.

Next Steps:

Lesson 5

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5:50 PM, Thursday April 20th 2023

Wow, that was amazingly in depth, and I especially appreciate the links to example images, and the markings on my work that show what to do differently next time! I can see a lot better now what the whole wrapping forms thing means! Thank you!!!

I think I can see what rules apply in deciding which parts of the drawing are supposed to be transparent vs. opaque.

That is, the initial balls and sausages of the animal constructions are all transparent like glass, but the wrapped forms that add mass get blocked by the thing they are wrapped around. Each wrapped form is also opaque to itself.

Simplest example: the box blocks back view of the squished ball, and you cannot see the far side where the ball touches the top of the box (only the close side labeled as "bottom side presses against box...etc...): https://i.imgur.com/IINKdQA.png . However, you can see the back corner of the box, and you can see the box through the ball.

It seems the dog leg shows transparent balls and sausages, as well as wrapped forms that you can't see the back of)

6:04 PM, Thursday April 20th 2023

Yes, your understanding of how to handle both the basic armature, and subsequent additional masses is correct.

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11:57 PM, Saturday April 8th 2023
edited at 12:17 AM, Apr 9th 2023

Hey there,

Snail and the crab are my favorite! Nice work.

Re: Shadow Construction

This book goes into every aspect of shadow creation.

How to Render by Scott Robertson

To properly construct a cast shadow you need three things:

  1. Light Origin

  2. Shadow Origin (point which sits directly below the light source on the ground plane)

  3. Vanishing Point

The basic Idea is to draw a line from the shadow origin and another from the light origin. You want to draw the lines so they graze the outline/contour line and continue until they hit the line from the other origin. Where they intersect is the outer edge of the cast shadow - do as many lines from each origin as you need to get the outline.

Here's a simple diagram of the technique.


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edited at 12:17 AM, Apr 9th 2023
4:37 PM, Tuesday April 11th 2023

Thanks so much, especially for the shadow info!

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