Structure Basics – Making Things Look 3D
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Structure Basics – Making Things Look 3D
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Mathias Ragnarsson
I face the same kind problem with simplifying the shapes as I do with gesture drawing. It’s a challenge to not think of the contour when drawing gestures, and with this exercise it’s a challenge to not make the shapes more complex than they have to. I realize I’m not using too many primitive forms here, but I want to post this anyway and come back to it later as I progress.
LESSON NOTES

Basic Building Blocks

structure basics 3d building blocks sphere cube cylinder

Just like gesture had the three basic lines, csi, structure also has its three basic building blocks. Spheres, cylinders and cubes. You can simplify pretty much any organic object into these three forms or a combination of these three forms.

You can also stretch and bend these forms to better fit the character of the subject. A sphere can be modified to an egg shape, a cylinder can taper thinner to one end like you’d see in a leg. At its extreme, a tapering cylinder would become a cone.

structure basics stretch and bend forms

A cube can be stretched to be more rectangular. And the sides don’t have to be the same size. You can taper thinner to one end like with the cylinder, bend it to follow the gesture of the pose, and even twist it. Basically, think of these forms as if they’re made of playdough. You can deform them as you wish.

structure basics 3d stretch bend twist forms like playdough

We construct from these basic building blocks because it’s a lot easier to imagine simple forms 3-dimensionally then complex forms. It’s a lot easier to imagine and work out the perspective of this camel with boxes and cylinders. Then add the details of the anatomy. The same could be done with the figure. which I’ll go over in detail in the next few episodes.

basic building blocks for camel

Simplify the figure into basic spheres, cylinders and boxes. This will immediately give the figure a 3 dimensional look. Having established this 3D idea allows you to visualize and construct the finer details of the anatomy in perspective more accurately.

The difference of Spheres, Cylinders and Cubes

So let’s take a closer look at these simple forms.

You can simplify the rib cage and pelvis to spheres, cylinders, boxes, or combinations of these forms depending on what you need for that pose. The sphere is really just a circle, since a sphere without tone appears 2 dimensional. So, the sphere is flat when using line. It doesn’t tell us anything about the form and its orientation in space. If you stretch the circle into an oval, now we have one piece if information about its orientation. The oval will only tell us the tilting left or right.

To show any kind of leaning back or forward, we need to indicate a bottom plane or a top plane. That’s where the cylinder becomes useful. It shows the tilting with the angle and the leaning with the bottom or top planes.

We can go one more step forward and use a box. The box has one thing that the cylinder doesn’t – it shows us the edges between front, back and side planes. This shows us the twisting motion.

So now with these three options, we can choose the one that does the best job in describing the form of the pose we’re drawing. Sometimes a cylinder for the rib cage with a centerline to show the twist is enough. Sometimes the addition of the corners at the rib cage and pelvis to show the front and side planes is helpful. It’s up to you to decide how you use these basic forms.

structure basics 3d three basic building blocks sphere cude cylinder

Drawing Cylinders

Start constructing cylinders by finding the angle, the length and width. This establishes its placements and size. If the cylinder is foreshortened make sure to slightly taper the sides thinner towards the far end to indicate foreshortening.

Then it’s time to identify the cross contours. Ask yourself if you’re looking up or down at the cylinder and how much. Based on that, add the ellipses of the top and bottom planes. Make sure to keep the angle of the ellipse perpendicular to the angle of the sides. The common mistake is to make the angle vertical or horizontal.

Another common mistake is when we indicate the cross contour lines, we tend to make them flatter than they really are. The thing about cross contour lines, is that most of their effect is on the sides. That’s where the roundness of the form is revealed. So don’t flatten them and bring them to a sharp corner with the edge of the cylinder, that defeats the purpose of the cross contour line. It should feel like it’s wrapping around the edges.

Drawing Boxes

You should be able to draw a 3d box from imagination at any angle. In the illusion of depth series I talked a little about perspective. A box’s edges will converge to a vanishing point on the horizon line. This works well for structures like a house where the bottom plane is parallel with the ground. When you rotate the boxes it gets much more complex and personally I feel it’s too complex and too mathematical to think about all that stuff when drawing a figure.

converge to vanishing point tilt cube

So, develop a sense for perspective and use your intuition. You’ll get better with practice, but a few tips will get you pretty far right away. The way I approach it is at first I imagine which planes of the box I’m seeing. You’ll see 1, 2 or 3 planes. If you’re looking directly at one side, like the front, it’s just a rectangle. When the box rotates down, you start seeing the top plane. And when it rotates to one side, you’ll see one of the side planes.

Also, notice that all the lines are converging to create a sense of depth. Look at this box and see if you draw boxes this way... If you draw boxes this way, stop! This is an impossible box. Things appear smaller as they move away from us. So, drawing all these parallel lines removes the perspective from the scene. And if this plane is a rectangle, that indicates we're looking directly at it. If we were looking directly at it, none of the other planes would be visible. In this case, since we're seeing some of the right side, the front plane is starting to rotate away from us. The lines here would converge to the left. And since we're seeing the top plane, the front and side planes are rotating downward. So, the lines would converge down. Now that's a much more 3 dimensional box.

structure basics 3d correct approach to draw a 3d box

Let’s try a step by step approach and see if this helps you. I’ll start with the inside edges of the box. The most vertical one is a good starting point. Is the box leaning to the left or right, and how much? Establish that with the first line.

Then, are you seeing the bottom or top of the box? If you see the top, then the other two inside edges will be attached to the top of the initial line.

How much of the top are we seeing? If it’s a little, the lines will be flatter with an obtuse angle. A lot and they will have more of an acute angle.

Also at this point you’re thinking about how much of the front and right side you’re seeing. The same of each would make the angles of these lines equal. If you see more of the front, that side will be more horizontal and the other side more vertical since its moving away from us more. And vice versa…

This is the foundation. It tells you the orientation of the box. After this it’s really easy. Just go to the end of each line and connect the outside edges with converging lines.

Consider the lengths of the initial 3 lines. If it’s a perfect box then you just need to think about how much each side is being foreshortened depending on how much it’s facing away from you. But if some sides are longer than others, think about that length and foreshortening.

As you can probably tell, this isn’t something that you’ll get right on your first try. It’s a bit confusing so you need to repeat the process many times to get familiar with it. It’s critical that you do get familiar with it if you want to apply these concepts to a complex form like the figure. Next week we will talk about the robo bean which is a 3d representation of the torso. So, go practice your boxes by looking around you for boxy furniture and drawing them from different angles. Then try inventing them from your mind…

practice drawing boxes from different angels

Premium Section

If you want to see more detailed explanation of this video and all the other videos from the figure fundamentals series check out proko.com/figure. For every free video that I post during this figure series, I’m posting additional premium content on proko.com. This week I explain more about the position of the viewer, avoiding flat perspective and how to simplify forms. So far there’s a total of over 3.5 hours of video in the premium section, so lot’s of goodies there.

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ASSIGNMENTS

Start by practicing cylinders and boxes of the things around you. Here you’re using observation and what you know about structure to draw the forms. Then move on to drawing them from your imagination. Can you imagine a box in your mind and draw it exactly how you imagined it?

When you’re ready, get some reference of animals and try to simplify them into balls, cylinders, and boxes. Avoid flat angles. Try to find dynamic angles of the animals in motion. That will be a much more valuable exercise.

Post your work and participate.

Newest
@adisuba
3h
Here's my attenpt of a rhino
Lucijan Prpić
Alison Shelton
Looking at what others have done here, I may have simplified too much.
Alison Shelton
Juice
2mo
Alison Shelton
I can really see the motion.
Tommy Pinedo
Very cool! I wonder what kitty is chasing. 🤔😃
@rcruey1027
Emm Rdgz
2mo
@trait
2mo
The monkey is so cool ! These are all great looking shapes !
Juice
2mo
This one was very hard. Not so much the simplifacation of form. But the structure/perspective with the cross contoure when i need to decide from Wich direction I see the form. Especially on the limbs.i wanted to make the knees as boxes but that made me very confused. I got som imposible connectioms where i saw the upper leg from below (cause it going forward) and i saw the knee from abow. So I made blobs instead. But i could probably have solved it with a gap between leg and knee. Or make the the as to boxes angled differently anyhow. Here is my horse :)
Alison Shelton
You did a beautiful job
Juice
2mo
Patrick Bosworth
Really nice shape breakdown! Clean line quality, accurate proportions, get job! I like that you kept things sketchy and cleaned up with tapered strokes on the cat. The dog looks really clean too, keep up the good work!
mike mcdonald
I struggled with the arms and legs connecting to the body, it was hard for me to identify those connecting shapes.
@fifiyellow
@deadsm
3mo
Definitely out of my comfort zone but I am inspired by everyone here.
Amortquio Flores
Here's my assignment for this class. Dunno how I did, but I did it.
Melanie Scearce
This is a great start! I like the shapes you used to break down the structure. Keep it up 👍
Gavin Hubbard
These look great!
Prew
3mo
Do u guys have any feedback about those drawings? Especially in forming them 😔🙏🏻
Jack
4mo
Tricky. Lapsing more into gesture than structure, I definetly need more constraints and maybe more practice with basic shapes.
@sweethouse
Here are my attempts for the assignment, I chose some pretty dynamic poses for my horses and one of the cats. My question is, would I have been better off simplifying some my forms even more, such as the torsos of the animals. I didn’t end up making them straight cylinders, but still tried to give them some 3 dimensional form.
Tommy Pinedo
Here are my attempts for this assignment. Did some warm ups of boxes and cylinders than the animals. I wasn’t happy with the eagle one but decided to show it anyway. @Rachel Dawn Owens I have a question, It felt more natural for me to construct forms using boxes and cylinder's compared to beans and gesture. is that normal part of the learning process like a sort of stepping stone? or could this indicate that I naturally lean more toward construction based thinking vs gesture first approaches? just curious if this is something others experience too, or if it might be a sign of my drawing instincts leaning a certain way? Thanks so much in advance! You’re the best. 😊
Rachel Dawn Owens
Some people find gesture easier, some people find structure easier. It’s natural to lean one way or the other and it can become part of your voice as you develop. You still want to want to learn both gesture and structure in order to improve. People who think more analytically seem to have an easier time with the constructive stuff. You can’t overthink gesture drawing. Have fun with it and don’t worry so much about getting them ‘right’. And these are amazing structural animal drawings! There’s a ton of depth here. Bringing forms forward with heavier lineweight is a pro move. Great job!!
Michael Longhurst
Animal structures newest to oldest. The three newest were after the critique. I felt like I started to get it more when I studied one animal, horses, then lizards.
Rachel Dawn Owens
Those horse studies are awesome!
L Kelly Jr.
Here is my structure assignment. I felt like I was able to mix gesture and structure enough to create something that showed improvement.
Melanie Scearce
You're getting it! Keep working on dialing in your line quality. Try to lay in your searching lines a bit lighter and only darken the ones that are final. These are good structural drawings overall, keep it up!
pell
6mo
I followed the suggestion of @Rachel Dawn Owens to go larger when studying the basic forms in a figure. I agree. I felt a lot more comfortable having more room to judge proportions and shapes. Of course, daily gesture practice has been helping too. I did start down a couple of sideroads I should have avoided, but the angry locals chased me back to the main highways.
Rachel Dawn Owens
This looks great!
pell
6mo
This time I looked for the basic structure of the figure with basic forms more closely conforming to the forms of the figure.
Rachel Dawn Owens
Looking good! Maybe try some bigger drawings too! It will be easier to keep it clear.
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