1. TECHNICAL DRAWING II
© Federico Fernández Herrera
ENGLISH BILINGUAL 1º E.S.O.
VISUAL AND PLASTIC EDUCATION
DIDACTIC UNIT # 6

2. TECHNICAL DRAWING II
* Drafts and sketches.
* Drafting scale.
* Diedric system.

3. TECHNICAL DRAWING II
* Drafts and sketches
DRAFT: It is a free hand drawing (just with a pencil). We show
an idea or object without totally defining it.
WARNING:
A DRAFT IS NOT A BAD DRAWING,
A SKETCH IS NOT A GOOD DRAWING !

4. TECHNICAL DRAWING II
* Drafts and sketches: example of draft

5. TECHNICAL DRAWING II
* Drafts and sketches
SKETCH: It is a free hand drawing too, but it
includes the measures, therefore it shows the precise
size and a shape similar to the final drawing.
measure

6. TECHNICAL DRAWING II
* Drafting scale:
We define scale as the relation between the drawing size and the
real object.
A model uses a reduction scale

7. TECHNICAL DRAWING II
* Drafting scale:
D:R
Drawing size Real size

8. TECHNICAL DRAWING II
* Drafting scale:
Scale types:
* Reduction scale: it is used to represent big objects,
so they can be drawn on paper
We usually use: 1:2 1:5 1:10…
In this example we have reduced 1000 times the real size of
the tree.
* Enlargement scale: it is used to represent small
objectsso we can see them on paper
- Itis used: 2:1 5:1 10:1 …
In this example the drawing is two times the real object.

9. TECHNICAL DRAWING II
* Drafting scale:
2:1
Scale 2:1
Real

10. TECHNICAL DRAWING II
* Drafting scale:
2:1
Scale 1:2
Real
1:2

11. TECHNICAL DRAWING II
* Drafting scale:
2:1
Scale 1:4
Real
1:2
1:4

12. TECHNICAL DRAWING II
* Diedric system:

13. TECHNICAL DRAWING II
* Diedric system:
The projection or VIEW consists of drawing just what we see
when we are perpendicular to the object and to the plane

14. TECHNICAL DRAWING II
* Diedric system:
To define an object we only need 3 views, floor, front and
profile:
Floor view: from the top of the object
Front view: facing the object
Floor view
Profile view: from the side
Profile view
Front view
Profile view
Front view
Floor view

15. TECHNICAL DRAWING II
* Diedric system:
Diedric Rules
The front is usually indicated with an arrow
The views distribution
The front is always on top of the floor
The profile is situated the other way round, that is, the
left profile is situated on the right
Right profile front front Left profile
floor floor

16. TECHNICAL DRAWING II
* Diedric system:
Remember:
The same height: the object has the same height on the floor and
on the profile views
The same width: on the front and on the floor views
The same depth: on the floor and on the profile views

17. TECHNICAL DRAWING II
* Diedric system:
Now try to figure out the views of this object.

18. TECHNICAL DRAWING II
* Diedric system:
This would be the result.

19. TECHNICAL DRAWING II
* Activities:
1. Draw a sketch of your home wardrobe (cupboard).
2. What are the real dimensions of the car? (E 1:100).
2.5cm
4.5cm
3. Draw the front, left profile and floor views of your pencil
marking the measures.
4. Where do we have to be placed to see these objects like circles?