graphic expression
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GRAPHIC GRAPHIC EXPRESSIONEXPRESSION
GRAPHIC GRAPHIC EXPRESSIONEXPRESSION
Lesson 2. 1st termLesson 2. 1st term
Perspective in drawings• We use projection drawings to represent 3D
objects in two dimensions (our paper)• There are two types of projections:
Cylindrical (Orthogonal) Conic
(x, y, z)
VPVP
•No distorsion
•Vanishing point (VP) far away
•Objects are distorted in the same way our eyes see them
•Vanishing point close
First angle projection• Cylindrical projection composed of
three views (taken from very far away) of the object:
side
front
top
First angle projection: result
front side
top
Oblique projection• We represent one of
the faces (mathing with X and Y axis) in true dimension and the others are distorted.
Y
Z
X
Representing objects in oblique projection
Y
Z
X
We have to consider the X, Y and Z axis.
We first draw the front face of the figure (X and Y axis
Then we draw the sides corresponding with the z axis with a reduction coefficient of 1/2
We finally close the figure with the lines corresponding to the back of the figure
Axonometric projection _ Isometric projection
• Axonometric projection shows an object from the corner so we see its three sides
• Objects seem distorted because the same scale is used for all features
• One axis is drawn vertical and the others are at an angle.
120º
120º 120º
Isometric projection
Drawing objects in isometric projection
120º
120º 120º
Isometric projection
We draw according the axis at 120º angles
We first draw a figure’s corner
Second we draw the lines which correspond to the sides next to the corner, corresponding with Z axis
Then we draw the lines corresponding to the left and rigth cornersWe first draw a figure’s corner
Two point perspective
2 VP1 VP
Draw an horizontal line across the page and mark two vanishing points: VP1 and VP2
Draw one corner of the box: vertical lineDraw the construction lines from the top and the botton of the corner to the vanishing point
Draw two vertical lines corresponding to the left and rigth corners. They go from the top to the botton lines
Draw the last construction lines from the top and the botton of the other corners
Complete the box using the construction lines
Single point perspective
First draw the front of the cube. Then add a vanishing point (X)
Draw thin construction lines from each corner to the vanishing point
Draw the lines which correspond to the back of the figure
Draw the rest of the figure over the segments of the construction lines
VP
Dimensioning• To dimension means “to indicate the
real size of an object in its drawing”
45
70
25
50
Scale
Magnitudes and units• Magnitude is a physical
property which we can measure / determine / quantify: i.e: length, mass,…
• Units are the symbols which go after a number and identify the magnitude we refer to
Types of magnitudes• Fundamental: we can express or
determine them with a direct measurement: there are seven: mass (M), length (L), time (t)
• Derived (derivadas): they are obtained by combining the fundamental magnitudes: force, volume, surface…
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