Lesson video

Hi, I'm Mr. Bond.

And in this lesson, we're going to learn how to sketch three dimensional shapes, when given the plan and elevations.

Let's get straight into our first example.

We need a front elevation, a side elevation, and a plan so that we can sketch a 3-D shape using them.

So we'll use this front elevation, this side elevation, and this plan.

So we can see that we've got three rectangles, one 3 by 5 centimetres, one 3 by 2 centimetres, and one 2 by 5 centimetres.

When sketching 3-D shapes, it can be really useful to use isometric paper.

The distance between the dots on an isometric paper is 1 centimetre, and also the squares on our square grid are 1 centimetre by 1 centimetre.

So it makes sense to use isometric paper.

So the first thing that we're going to do is draw the right-hand side of the front elevation.

This is a line segment 3 centimetres long, and here it is on my isometric paper.

Next, we're going to draw this edge of the rectangle.

This is a line segment 5 centimetres long, and it connects to the bottom of the first line segment that I drew.

Here it is on the isometric paper.

Next, I'm going to draw the left hand side of the rectangle.

And this is a line segment 3 centimetres long.

So again, starting from where I finished on the isometric paper, here's that line segment.

And finally, I need to connect the end of this line segment to where I started to show the top of the front elevation.

And that's this line segment here.

Now let's think about the side elevation.

We'll start by drawing this edge.

This is 2 centimetres long.

Here it is on the isometric paper.

Now, we'll draw the right-hand side of the side elevation.

This is a 3 centimetre line segment, and needs to start where I finished the bottom part of the side elevation.

So that's here on our isometric paper.

Next, we're going to draw the top of the side elevation, and this really just completes the rectangular face that we can see.

And that's here on our isometric paper.

So now I've completed the front and the side elevations.

Finally, we need to think about the plan.

This part of the plan has already been drawn on the isometric paper.

So we just need to think about the other two sides.

So we need to think about this line segment, 5 centimetres long, which would go here on our isometric paper.

And finally, the left-hand side of the plan, which is a line segment 2 centimetres long and complete our shape.

So we can see now that we've drawn the front and side elevations and the plan, we've drawn a sketch of a cuboid.

If you wanted to, we could draw dotted lines in like this, but you don't have to.

Here's a question for you to try.

Pause the video to complete your task and resume the video when you've finished.

Here are the answers.

Hopefully, you realised that this was a triangular prism.

Something extra to think about here is when you look at the plan of the shape, is the rectangle that represents the plan the same dimensions as the rectangular face that you can see? Here's another task for you to think about.

Only prisms can be represented by plans and elevations.

Is this true or false? It's false.

If you want to practise drawing some plans and elevations of shapes that aren't prisms, here are a couple that you could make out of cubes and see that we can draw any 3-D shape using plans and elevations.

Here's another question for you to try.

Pause the video to complete your task and resume the video when you've finished.

Here are the answers.

Hopefully, you've drawn a hexagonal prism similar to the one that's on the screen.

There are two things that we needed to notice here.

First of all, the front elevation is a hexagon.

Secondly, both the plans and side elevations have extra line segments to tell us that they're made of more than one rectangular face.

That's all for this lesson.

Thanks for watching.