Name: WORKSHOP (Week 7): Construction of Spheres and Spherical-based forms
Uploaded: 2024-10-13T17:17:12.000Z
Duration: 15 min 59 s
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Hi again everyone in this video. I'm going to cover the fundamentals of constructing spheres and spherical forms

We will have a look at how to fully construct a sphere in stages

But let's have a look at what makes a sphere look like it's in perspective

So here you can see we have six spheres drawn from different perspective angles

The silhouette of the sphere of course is just a circle

But it's the contour lines that help communicate what perspective angle they're drawn from the contour lines are based on three intersecting ellipses and

You can see here me tracing off those ellipses. There's the first one there's the second one and

And those ellipses are based on the intersection of three planes

So let's simplify this and just take a look at one sphere from one particular angle in order to

Understand how to construct these things. So here I have two spheres and these spheres are sitting on a horizontal surface

How do we know that they're sitting on a horizontal surface?

Well, if we have a look at our ellipse lying horizontally

The major axis is horizontal to our view that ellipse would be sitting in a square

That is horizontal and our minor axis is straight up and down vertical

This particular drawing is showing that we are slightly above the sphere

Drawn closer to our eye level and what's the rule?

Well, the flatter the minor axis is the closer it is to the horizon line

So we're still using the same principles that we've learned about sketching ellipses in perspective

So let's take the perspective angle of this sphere and I'm going to use it to show you how to fully construct

This sphere in stages using three intersecting planes

So here we have the redrawn sphere using color-coordinated contour lines

To the right. This is the full construction of that sphere. You can see here. I've drawn a very light estimated perspective cube and

It's important to have your proportions correct particularly of the square planes

That we know that the ellipses are going to sit inside

The more accurate your ellipses are going to be the more accurate the contour lines to indicate surface are going to be

Now I've left out the major and minor axes from this sketch just to keep it cleaner but take note of the major axis of this red ellipse and

The minor axis is actually a line going to the left vanishing point on this green ellipse the major axis

Is 90 degrees to the minor axis and that minor axis is going to the right vanishing point

Of course our blue ellipse, which is a horizontal ellipse its minor axis is vertical and major axis is horizontal and 90 degrees to that minor axis and

Just to clarify that here. I'm just showing the three

Ellipses on their individual planes, and I've indicated the major and minor axis of each of those ellipses

Vertical ellipse, which is this green one the minor axis would be going to the vanishing point to the right

And on the left vertical plane, which is this red ellipse its minor axis would be going to the left

Vanishing point and of course the horizontal ellipse, which is this blue one. We have the centerline which is vertical

That's your minor axis 90 degrees to that would be your major axis the view up here is the same construction, but without the full construction of the cube and

You can see that we've got the three intersecting planes and the ellipses that sit on those planes

We're going to use this view to help us construct

Radiused corners, so let's have a closer look at that

Firstly let's have a look at a cube that has radiused corners, and you can see this cube here

Which started off with sharp edges and sharp corners has actually been rounded off with radiused corners

Each of these images here are actually part of the construction of a sphere

So this bottom corner here bottom left corner

This sketch doesn't show the construction of the far side top corner, but in fact if we joined all of these corners

Together we would actually make up a sphere

The outer images shown here are basically each of these corners without the full construction

So in heavier line weight that would be the object as a solid or the corner as a solid and of course light line work to show the internal construction of that edge

Corner, and of course the far side right corner and again the bottom left corner

The bottom leading corner and the bottom right corner drawn without all of its construction

So let's see how to construct each of these corners by using our early image showing the intersecting planes and ellipses

Okay, so here you can see I've digitally replicated the construction of a sphere

Using the construction with the three planes and the ellipses and from this I'll show you how to construct

The radius corners on the top surface of this sphere

You can see there are four quarters or four quadrants on the top surface above that horizontal plane and each of those

Corners are actually little cubes and we can take the top left corner to construct this radius corner

There's the leading radius that part of the ellipse will also have that part of the horizontal ellipse

This part of the green ellipse on the right vertical side and

The radius of the circle to construct the far side radius corner we would take the far side cube

Define the base edge or the baseline edge

Trace off the sections of the ellipses on the left vertical face

Here we have the top right radius corner and it's basically the flip side of the top left radius corner

Again we trace off the vertical edge horizontal edge that part of the right vertical ellipse

This part of the left vertical ellipse it will tangent the radius of the circle

Part of the horizontal ellipse and of course that should tangent smoothly to the perimeter of the circle itself or the sphere itself

And the last of the four radius corners on this top surface would be the forward facing radiused corner and you can see

We're taking this section of the horizontal ellipse that section of the left

Vertical side ellipse and this section of the right

Vertical side ellipse and that's it. If I wanted to show the inside construction of each of these radius corners, of course, you can come in with lighter line weight and define these construction lines

So that's if we want to show all the internal construction

I'm using a finer point fineliner to do this and

Obviously these aren't shown on the images on the top row here

Okay, so let's now have a look at constructing the radius corners on the bottom surface of this sphere

Four little cubes and we trace off the edges and parts of the radius of these ellipses to construct our corner

So with the bottom left radius corner, I'm tracing off

That horizontal and vertical line it gives me a sharp edge and corner

Then of course, I'm going to trace off this section of the horizontal

Ellipse this part of the left vertical ellipse and here's the tangent which would be the outline or the perimeter of the circle

The far side lower radius corner which would be the box at the back of this lower surface we would see a leading corner

Then I would have this section of the yellow ellipse, which is that left vertical ellipse this section of the right vertical ellipse

And of course that section of the horizontal ellipse

Moving along to the right side lower radius corner

I'm tracing off again an edge that I can see

Oops a little bit wonky and then I would see that this section of the top

Vertical ellipse, which is the green one and of course the perimeter of the actual sphere itself and

Subtitles ListPlay Video

WORKSHOP (Week 7): Construction of Spheres and Spherical-based forms

perspective

slightly

basically

structure