Download UNIT 1: Technical drawing: the basics. Working with lines

VISUAL ARTS 1ST ESO
THEORY
UNIT 1
UNIT 1: Technical drawing: the basics. Working with lines
Basic tools
The set of squares
The set of squares with the compass are the basic tools in technical drawing.
These tools, usually made of plastic are two square triangles (triangles with one of their
angles of 90º)
30o
45o
90o
60o
6OO SQUARE or TRIANGLE
90
o
45o
45O SQUARE or TRIANGLE
With the set of squares we can obtain many different angles (15º 30º, 45º, 60º, 75º, 90º,
105, 120º, 135º, 150º, 165º, 180º) by adding or subtracting them.
Image taken from https://laclasededibujo.wordpress.com/contenidos-2/instrumentos-de-dibujo/
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VISUAL ARTS 1ST ESO
THEORY
UNIT 1
With them we can also draw parallel and perpendicular lines.
Parallel lines are straight lines that follow the same direction, so they never cross
Image taken from https://laclasededibujo.wordpress.com/contenidos-2/instrumentos-de-dibujo/
Perpendicular lines are straight lines that cross making 90o angles
90o
90o
90o
90o
Image taken from https://laclasededibujo.wordpress.com/contenidos-2/instrumentos-de-dibujo/
LINES CLASSIFICATION
According to their shape, lines can be:
CURVED
WAVY
DOTTED OR DASHED
STRAIGHT
BROKEN
CURLY
ZIGZAG
SPIRAL
TAPERED
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VISUAL ARTS 1ST ESO
THEORY
UNIT 1
According to their position lines can be:
VERTICAL
HORIZONTAL
DIAGONAL
According to their relation with other lines they can be
PARALLEL
CROSSING LINES
PERPENDICULAR
900
THE COMPASS
This tool is used to make circumferences …
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VISUAL ARTS 1ST ESO
THEORY
UNIT 1
….but also to transfer measures…
Addition of segments
Subtraction of segments
Image taken from http://plastinloca.blogspot.com.es/2014/02/lamina-22-disena-tus-iniciales-suma-y.html
Transferring (copying) angles
Addition of angles
Subtraction of angles
Images taken
from http://www.profesordedibujo.com/index.php/videos/trazados-geometria/trazados-fundamentales.html
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VISUAL ARTS 1ST ESO
THEORY
UNIT 1
Basic constructions
Bisector of a segment
Definition: The bisector of a segment is the perpendicular straight line that divides the
segment into two equal parts, creating square angles (900 degrees).
We can obtain them using the compass and the ruler …..
1. Open the compass more than the
half of the length of the segment.
2. Place the compass in P and draw
an arch
3. Place the compass in Q and draw
other arch that crosses the first
one
4. Draw a straight line that links the
two points where the arches
cross.
This blue line is the bisector of
PQ segment
……or with the set of squares:
1. From P draw a 300 angle above the
segment and other of 300 bellow it
2. Do the same in point Q
P
300
300
Q
3. The straight line that links where the
angles cross each other is the bisector.
(the thick line)
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VISUAL ARTS 1ST ESO
Bisector or an angle:
THEORY
UNIT 1
Definition: The bisector of an angle is the straight line that divides the angle into two equal
parts
THALES THEOREM (Application)
When we want to divide a segment into a certain number of equal parts we have to apply
the Thales Theorem
Example: ”Divide this segment into 6 equal parts”
Step 1
Step 2
Step 3
Step 4
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