Hello and welcome to this design and technology lesson.

My name's Mrs. Fletcher and I'm here today to help guide you through this learning about cross-section drawing.

And this lesson, developing ideas through cross-section drawing, is part of the Cams: Automata unit.

I'm really looking forward to getting started, so let's have a look at what we'll be learning about today.

In today's lesson we're going to be learning about cross-section diagrams, and they're a type of drawing that are used as part of the design process to give more information and detail about a product.

And by the end of today's lesson, you'll not only understand how they are used in the design process, but you'll also be able to draw your own cross-section diagram of a product.

So let's have a look at the keywords that we are going to need in today's lesson.

The word cross-section itself refers to the inside view of a 3D object when it's been cut straight through.

So if you imagine a product that's been cut in half, that new view of the inside that you get is a cross section.

The plane is something we'll also be talking about, and that's a completely flat surface that goes on forever in all directions.

We're going to need use to use the word vertical, which is that up and down direction or position, and the word horizontal, which is that side to side direction like the horizon.

So let's have a look at how our learning will be broken down today.

So first of all, we're going to have a look at understanding cross-section diagrams, what they are, and what they look like.

And then we'll move on to developing our own ideas for using cross-section drawing.

And then we'll use those cross-section diagrams to present our ideas at the end.

So let's get started with understanding cross-section diagrams. A cross-section is that internal, that's the inside view, of an object that cannot be seen from the outside.

Imagine cutting something in half.

So here we've got a piece of fruit, a kiwi.

Imagine if you cut it in half and you can see the inside.

That new view of the inside of the product is the cross section.

Cross-section diagrams are often used to show the internal view of a three-dimensional object in two dimensions.

And you may have seen this in some of your science lessons where you might have seen diagrams of the eye, or a bone, or a tooth where you can see the inside section that you wouldn't not ordinarily be able to see.

Cross-section diagrams are useful because they show us parts of something that we may not be able to see otherwise.

So imagine we are thinking about the layers of soil.

We can't ordinarily see down all those layers, but a diagram can show us how those layers might work.

The same can be said of looking at volcanoes.

We can't see inside a volcano, so we sometimes need a diagram that represents the inside of that volcano.

And something like the layers of the Earth in science.

If we are thinking about the layers of the Earth, we can't see them, but a diagram can help us visualise those layers.

Quick check then.

What does cross-section diagram show? Was it the external view? Was it a closeup view? Or was it an internal view? Pause the video and have a think.

Okay, what did you think? What type of view do we get from a cross-section diagram? Well done if you said it was the internal view.

So that word internal means inside.

So we're seeing the inside of a product.

Cross-section diagrams can be drawn from either a horizontal, which was the left-to-right horizon line, or a vertical which was the up and down position perspective.

So we can draw them from one of those perspectives, and those are called the planes.

Imagine this as the direction of the cut.

So if we were to cut something in half, whether we cut it vertically or horizontally, that's what we refer to as a plane.

So here we have a cylinder shape.

If we cut that in half on a horizontal plane, so cutting from left to right or right to left, it would look like this.

But if we're cutting it down vertically, we would get a different view of the inside of that shape 'cause we've cut from top to bottom.

Vertical and horizontal planes can provide very different views of the inside of a product.

So if we think about that cylindrical shape, if I use a horizontal cut and cut through the middle of that shape, then the view that I see is that circular shape looking down on the product.

But if I was to cut it vertically from top to bottom, then I would actually see a rectangular shape as my new view of that product because the cut that I've done means I can see into the side of that product which is a different shape than looking down on that product.

So you can get very different views by cutting horizontally or vertically.

So horizontal and vertical planes, do they show the same view? Is that true or false? Horizontal and vertical planes show the same view.

Pause the video, have a think.

Well done.

Of course it was false.

They don't show the same view.

The shape of an object can be different when viewed from above or from the side.

We can see this difference when we cut open fruits and vegetables in different ways.

So if I was to cut a tomato in a vertical plane, so through from top to bottom, then the viewing side would look a little bit like this diagram here.

But if I to take the tomato and cut it across the middle on a horizontal plane, then I would be able to see a slightly different view inside that tomato.

So the view that we see depends on the plane that has been cut.

So, time for a quick task in this first part of the lesson.

Can you match these 2D cross sections to the 3D products underneath? So you're looking at the 2D internal drawings that represent a 3D product.

Can you match those together? And when you've done that, can you label each cross section to say whether it was cut on a vertical or a horizontal plane? So you're matching the product to its internal view, and then labelling it with a vertical or a horizontal plane.

Pause the video and come back when you're done.

Okay, welcome back.

How did you get on? Did you manage to match those drawings to the 3D product they represent? Let's have a look at what we should have.

So that first diagram, cross-section diagram, is actually an internal view of an orange.

The second diagram is the internal view of a tree trunk.

The third cross-section diagram is an internal view of a house.

And the final one was the internal view of an eye.

Well done if you managed to match those correctly.

But did you also manage to say whether they had been cut on a vertical or horizontal plane? Let's have a look.

So the orange has been cut on a horizontal plane.

So that means it's been cut across through the middle, a little bit like the tomato we saw earlier.

The tree trunk has also been cut on a horizontal plane.

So that's what the tree trunk would look like if it was cut horizontally through the middle.

The third diagram has been cut vertically.

So that's a house that's been cut in half from top to bottom to be able to get that view of all of those floors in the house.

And the final one is a little bit tricky 'cause it could be either vertical or horizontal.

Because the eyeball is the same shape all the way around, it would look the same if we cut it from top to bottom or if we cut it across the middle, it would have a very, very similar view.

So you were right if you said vertical or horizontal for that last one.

Well done.

Okay, let's have a look at the second part of our lesson now.

So we are going to be developing our own ideas now around cross-section diagrams. Now cross-section diagrams are used by lots of different people.

Architects, engineers, scientists, geographers, product designers, product manufacturers all use them for different reasons.

Can you think what each one of those examples might use cross-section drawing for? Pause the video, have a think, talk to a partner, or write down some of your ideas and come back when you've had a go.

Okay, so you may have discussed some things like architects might want to show the inside of a building.

Engineers would like to show the inside of a machine or of something that they're building.

Scientists might want to show lots of different things.

The inside of body parts, the inside of the Earth, the inside of planets, things like that.

Geographers might want to show the inside of volcanoes or the underground layers of soil, things like that.

Product designers might want to show how the inside of a product might look and how it might work.

And product manufacturers need those diagrams to be able to build those products to see what internal paths they need and to look at measurements and things like that.

So there's lots of different reasons why different people would use a cross-section diagram.

Quick check then.

Who wouldn't use a cross-section diagram in their job? So not everybody needs to use them, but so who wouldn't? Would a product designer, a hairdresser, or a scientist not need a cross-section diagram? Pause the video, have a think.

Welcome back.

What did you think then? Who would not need to use a cross-section diagram in their job? Well done if you said a hairdresser.

So a hairdresser doesn't really have any need to see the inside of any types of products.

Cross-section diagrams are used in product design to show how the product is made, how the parts fit together, and how it works.

So it's a very important part of the design process, and it's also an important part of the manufacturing process.

We need to be able to see not just what it looks like on the outside but how it actually works and fits together inside as well.

So here we've got a cross-section diagram of a torch.

Now from the outside a torch doesn't look very detailed.

We've got a plastic case, maybe a glass screen on one side and a button on the outside.

But if we actually look inside, then we can see all the components that make up that torch.

So we can see the light bulb, the power source, which is a battery in this case.

We can see how those pieces fit together and the position of them inside that product.

So it's important when designing and making these type of products to be able to see that kind of information.

Designers take their initial development idea sketches and they turn them into clear, accurate drawings that can be understood by other people.

So at the start of a design process we might just have a quick sketch of what the product is going to look like, and that's probably to be an external view, what it looks like on the outside.

It's our initial ideas.

But to be able to get other people to understand how this product might work and how to make it, they need to produce a more detailed picture, and that's where the cross-section diagrams come in.

They show a much more detailed drawing of a product that's designed to be made.

Quick check then.

Designers turn their sketches into what type of diagrams? Is it rough and inaccurate diagrams? Colourful and decorative diagrams? Or clear and accurate diagrams? Pause the video and have a think.

Welcome back.

Okay, of course it was clear and accurate diagrams. That's what's needed to be able to show other people how a product might work.

So you are going to be designing your very own automaton.

And an automaton is mechanical toy that uses a cam mechanism to animate a character or scene.

So we can see there on that little video we've got the animated characters at the top, which are penguins in this case, and a cam mechanism underneath which is causing the movement of those animated characters on the top.

So that's the product that you are going to be looking at designing and making.

A cam mechanism uses rotary motion from a crank and axle to turn cam discs, which then in turn causes followers to move up and down.

So this type of mechanism is used in this toy to animate the characters or scenes at the top.

So this is the products that you are going to be looking at quite closely.

Can you match these cams? So the snail cam, the eccentric cam, the pear cam, and the ellipse cam to the type of movement they make.

So one of those cams makes an up and down movement.

One of those causes a small pause in the movement.

One of them causes a sudden drop in the movement and one of them causes a jagged movement.

Can you remember which is which? Pause the video and have a go at matching those.

Okay, welcome back.

So did you remember how each cam creates different movements? Let's have a look if you matched them correctly.

So we'll start with the snail cam at the top.

The snail cam causes a sudden drop in the follower because of that lip on the side of the cam disc itself.

The eccentric cam causes a smooth up and down movement 'cause there's no extra bits on that circular disc.

The pear cam, because of its shape, causes a small pause in the movement of the follower, and that's because of that wider bottom end means it spends longer in that position than it does in the top position.

And then the ellipse cam causes a kind of a jagged movement of the follower.

So those are all things we need to consider when we come to design and make an automaton.

Okay, time for a task in this part of the lesson.

So as part of this design process you are going to make some initial sketches.

So these are your ideas, and you need to think about what type of character or scene you want your automaton toy that you're going to make to have.

Think about what type of movement you want the character or scene to make.

Think about how many cams you'll need to create that movement, and what type of cam you'll need.

So the shape of the cam, which ones you'll need to create the movement that you need.

Now remember the movements of those cams were the eccentric cause a smooth, up and down movement.

The snail causes that sudden drop of the follower, so you get that sudden drop of the animated character.

The ellipse causes kind of a jagged movement where it's a little bit more of a faster up and down movement.

And the pear cause is a small pause, so we've got that up, and pause, and down, and pause.

It doesn't create that smooth movement that the eccentric one does.

So you'll need to think about those.

Now remember, design sketches do not need to be accurately measured.

So these are just your initial ideas.

You can do it on the worksheet or you can do it in any other way that you choose.

Pause the video and come back when you've had a go.

Okay, welcome back.

So, your design should have been sketched and it should feature some of the characters or animations that you would like to have on your automaton.

So on my example here I've just quickly sketched my cam mechanism at the bottom, and I've decided to animate three smiley faces at the top.

So all I need to note at this stage is the shape or character, type of character that I've got at the top, where the box and the cams and the cam mechanism are going to fit in.

So yours should look a little bit something like this.

So there's my characters, there's my cam shape and number.

I've made a note of it on my design.

And I've remembered the movement of the cam discs, and that's why I've chosen eccentric cams and I've made a note of that on there.

You may have chosen different shapes depending on the movement you wanted your character to make.

So time for the last part of the lesson now.

So this is where we get to use cross-section diagrams to present those ideas.

So we've done some rough sketches, now we need to present them in a way that can be easily understood for us to make in the future.

In order to present the ideas accurately, we're going to turn those sketches into a cross-section diagram.

So in this example here you can see my development sketch, my initial ideas.

I've accurately drawn them in a cross-section diagram.

So we're gonna have a look at how that's going to work now.

You're going to draw the vertical cross section.

So that's as if we've just cut down the middle of your automaton, and we can see exactly what everything would look like from the side.

You are going to need a ruler and a sharp pencil to draw those accurate lines on your diagram.

Quick check before we start.

Which plane do I want you to draw your diagram on? Was it the vertical, the horizontal, or the front? Pause the video, have a think.

Well done if you said vertical, that's that cut down from top to bottom so we can see that side view of your automaton.

Okay, so a cross-section diagram should include other information such as the product name, measurements, and even the materials that the product will be made from.

So you can see here on my diagram I have added some more information from my initial sketch.

So I've added a title, I've called it the "Smiley Face Automaton." I've added some measurements to show that my characters will be 40 millimetres high, my followers will be 80 millimetres high, and the box will be a 100 millimetres by 150 millimetres.

So I'm adding in some extra information about the size, and then I've added some information about materials as well.

So I've made a note that the animated characters were made of cardboard discs, that the dowel that I use for the axle will be wooden, and the frame of the box will be wooden as well.

So those extra bits of information are important parts of the design.

You'll need to consider the measurements for each part of your design as well.

So for example, if my wooden frame here was 150 millimetres wide, I have to consider, like Sam's reminding me here, that if the box is 150 millimetres wide, the dowel is going to be longer than that because you can see that the dowel for the axle sticks out either side of the box.

So that means it must be longer than 150 millimetres.

So I need to consider each part in relation to other parts in order to choose a correct size for those.

So there I've chosen a size of 200 millimetres for my wooden dowel.

You're going to also include a side view of the cam mechanism itself and that will allow us to see both views.

So we're still looking at a vertical plane, but we are looking at a vertical plane looking from the front of the product, and a vertical plane looking from the side of the product.

And this will show us things that we can't see just on one view.

So here you can see, on my side view, we can see the size of the cams, you can see the position of those three cams, and you can see also the depth of the box, which you couldn't see on the front view in the previous slide.

So it gives a little bit of extra information.

Sam's also reminded us to label those parts, especially if they are things that you can't see clearly on that front view.

Now the materials you'll need to be able to make an accurate cross-section diagram is some squared paper, a ruler, and a sharp pencil.

Now I'm going to go through the steps of drawing an accurate cross-section diagram, and then you'll be able to pause the video and have a go at doing it yourself once we've been through all the information.

So first of all, you will need to accurately measure and draw the box section of your automaton design, and then the axle as well.

So thinking about the size that those will be.

And you could use the squares on the paper as a guide.

So if you've got 10 milli squared paper, then you can use that to measure out accurately how long or how wide your box and axle is going to be.

If you have smaller squared paper, then you can use the measurements on your ruler instead.

But I would use the lines of the paper to help you to line everything up correctly.

When you've done that, you need to draw the cams and the followers, including the characters on the top.

So this is where we draw how many cams we are going to have on the axle, the followers and where they will sit above those cams, and then how your characters will fit on top of those followers as well.

And then when you've done that, you're going to draw the side view and label both of the diagrams with the measurements.

So once you're happy that everything fits, then you're going to consider the measurements for each part.

Remember it needs to work in relation to other parts as well.

So you're going to consider all of those three things for your design.

Before you get started though, which of these are often included in a cross-section diagram? Do we see sentences? Do we see measurements? Do we see the price? Which one is often included? Pause the video, have a think.

Welcome back.

Of course it is measurement.

So it's very important that we know how big each part of the product is going to be.

So, time to get going on the task now.

So use the squared paper, a sharp pencil, and a ruler to accurately draw your cross-section design.

Make sure you include a product name, the accurately ruled lines using the squares, or at least the lines on the paper, measurements for each piece of the automaton, and notes on the materials and the colours that you are going to use and include when you come to make it.

You can go back to the steps that we've just been through, and then come back when you've done.

Okay, welcome back.

How did you get on? Hopefully you have an accurate drawing of your automaton taken from your sketch ideas earlier in the lesson.

Just make sure that you have included that product name to tell us what it's going to represent, what it's going to show us.

Accurate ruled lines, which follow the lines on the square paper.

Measurements for each piece of the automaton so we know exactly what size to make each component.

And some notes on the materials you're going to use or the colours that the materials are going to be.

So we're nearly at the end of the lesson now.

We've learned lots about cross-section diagrams, and hopefully you've seen how your initial sketch ideas for a product can be turned into very accurate, detailed drawing that can be used for making the product.

We've learned that a cross-section diagram is used to show the inside of a product or design, which can be very useful, especially when it's something you can't typically see normally.

The diagrams are usually shown on either a vertical or a horizontal plane.

So it's usually shown on one of those planes.

So you can either see it from a side view or you can see it from looking down.

And when drawing cross sections one plane is always the main view.

So we usually can't show a side view and the top view at the same time.

We choose one plane to represent the internal view of our product.

I've had fun learning about cross-section diagrams and having a go at drawing them as well.

Hopefully you now have a very clear, accurate drawing that you could use for designs in the future.

I hope to see you again in another lesson, but for me, goodbye for now.