Lesson video

Hello, my name's Mrs. Taylor and I'm really pleased you can join me today for our lesson.

And our lesson today is Plan Manufacture Using Orthographic Projection: Papers and Boards.

And this is from the unit Iterative Design: Nature.

We have five keywords: orthographic, which means represents a 3D object in 2D, where views are projected from the object's surfaces; third angle, which is a type of orthographic drawing; construction lines: guidelines which are used in drawings; dimensions: numerical values that specify the size; scale: a ratio of full size.

The outcome: "I can prepare an orthographic projection of my design." And in this lesson today we have two learning cycles: Planning an orthographic projection and Creating an orthographic projection.

Let's begin.

An orthographic projection represents a three dimensional object in two dimensions.

Views, such as front and side, are projected perpendicular to the object's surfaces.

They are sent from a designer to a manufacturer to enable them to manufacture the product or component on the drawing.

Orthographic Projections are completed before the manufacture.

Let's have a check.

An orthographic projection represents: A: a 3D object in 3D, B: a 2D object in 3D, or C: a 3D object in 2D? Pause the video and have a go.

Fantastic.

Let's look.

That's right.

It's a 3D object in 2D.

Here is an example of an orthographic projection.

Orthographic projections can be in first or third angle.

The positions of the views in the drawing are dictated by the angle.

Third angle projection aligns more naturally with how objects are observed in real life.

Here we have the symbol for the third angle projection, and you can see the centre line going both horizontally and vertically.

A centre line is a long dash and a short dash.

Let's have a check.

Identify what is missing from this third angle projection symbol.

Pause the video.

Let's check.

That's right, it was the vertical centre line.

The arrangement of the projections are shown below.

We have the front view, bottom left of your drawing.

The plan view directly above that on your drawing, and the side view to the side on your drawing.

We also usually have an isometric view of the product as well.

The distance between the front and the plan projections should equal the distance between the front and the side.

There are different line types on orthographic projection.

Outlines are a solid black line.

Construction lines are either grey if using a computer or faint if using pencil.

Hidden details are an equal spaced dashed line.

Dimension arrows are solid with an arrow at each end, and the centre line is a long and short dashed line.

Construction lines are guidelines that help create projections.

Centre lines are to indicate the centre of holes or symmetrical objects, and dimension lines are lines with arrow heads and a numerical value that specifies size.

Hidden detail are dashed lines that are not visible from the current viewpoint, and the outlines are to represent the visible edges and boundaries.

Here we have a check.

Describe the appearance of the different lines used on an orthographic projection.

Pause the video.

Let's check.

Outlines are solid black lines.

Construction lines are grey or faint pencil.

Hidden details are dashed lines.

Dimension arrow is solid with an arrow at each end.

And a centre line is alternate long dash and short dash.

Orthographic projections are created using a scale, and this will be recorded on the drawing.

A scale is the ratio between the dimensions of a drawing or model and the actual dimensions of the object it represents.

Reduced scales like 1:2 or 1:5 are most likely to be used, meaning the drawing is smaller than the real object.

Dimensions are numerical values that specifies the sizes in the drawing.

They are written once on the page and all dimensions are in millimetres.

A dimension arrow is used and the measurement is written above and in the centre of the line.

For example.

And the symbol for a diameter dimension is a circle with a diagonal line through it.

Task A: Label the following on the drawing: the projection names, the different line types, the third angle projection symbol, a dimension, and the scale.

Pause the video.

Wonderful.

Let's check.

So first of all, we have the plan at the top, the front, the bottom left, and the side to the right of the front.

And we also have the isometric drawing.

Next we can see a dimension at the top, of 250, and the arrow.

Outlines are dark black lines.

Construction lines are grey.

The centre lines are the long and short dashed, and hidden detail is equal space dashed.

And the scale is 1:2 in this drawing, and it has been drawn using third angle.

Well done.

Now we move on to the second learning cycle: Creating an orthographic projection.

Here is a design for a planter in an isometric view.

To create an orthographic projection, start by obtaining a sketch of the front projection and applying a suitable scale.

So here we can see an isometric view shaded, and we also have an isometric view with just the lines and the scale is going to be 1:5.

The arrows highlight the different projections used to create the orthographic drawing.

Front, plan, and side.

Align the front projection in the bottom left corner and add construction lines that support creating both the plan and the side projections.

So here we have the front projection, and now we can add construction lines going up towards where the plan drawing is going to be, and across to where the side view is going to be.

Let's have a check.

Identify the name of the view and projection for the design below.

Pause the video.

Fantastic.

Let's check.

The view is an isometric one, and the projection is the front.

Well done.

Sketch in the plan and side projections, applying scale.

The plan goes directly above the front view in line with those construction lines that we've already created.

And the side goes directly to the side of the front view, again using the construction lines.

Another check.

What is the name of the lines that support creating different projections? Is it A: dimension, B: hidden detail, C: construction, or D: outlines? Pause the video and have a go.

Let's check.

That's right.

They are called construction lines.

Well done.

Add lines for hidden details centre and dimension lines and dimension values to the relevant parts.

Extension lines can be added to show dimension extents.

For example, we can see here that we've got a centre line in the middle of the front view and we have hidden detail in the plan view.

An extension line is used to extend from the view to the dimension arrow to make it very clear which dimension it relates to.

An isometric view of the product is also added.

And then the construction lines can be removed.

To finish the orthographic projection, a title block is added.

This contains details about the drawing, like below: Who created it, when it was created, the fact that all the dimensions are in millimetres, so we don't repeat "mm" anywhere else on the drawing.

The projection symbol, the scale, the drawing number, because some complicated products may have several drawings, the company and then a signature from the creator.

So here we have an example of a final orthographic projection with all the details as we've described.

Task B: Create an orthographic projection for your design idea inspired by nature.

Use the following success criteria: Use an isometric sketch to create a front projection whilst applying a suitable scale.

Add construction lines to support creating the plan and side projections.

Add all relevant dimension, centre and hidden detail lines.

Add and fill in a title block with details including the scale.

Pause the video and have a go.

Wonderful.

Your answer could look similar to this.

Well done.

Here we have a summary of today's learning.

An orthographic projection represents a three dimensional object in two dimensions and is completed before the manufacturing stage.

A type of orthographic projection is third angle projection and consists of a front, plan, and side projection, along with an isometric view.

There are many different line types on an orthographic projection, including dimension and construction lines.

Projections are created using a scale, and this will be recorded on the drawing in a title block with other drawing details.

Thank you for joining me today and really well done.