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TECHNICAL DRAWING - Coggle Diagram
TECHNICAL DRAWING
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ORTHOGRAPHIC PROJECTION
Orthographic projection is a technical drawing method used to represent a three-dimensional object in two dimensions by looking at it straight-on from flat, perpendicular angles.
how it works
Perpendicular sight lines: You imagine looking straight at the object from different sides. The imaginary lines from the object to the paper always hit the surface at a 90-degree right angle.
Parallel lines: All the viewing lines stay parallel to each other instead of coming together at a single point, which is what happens in a realistic 3D picture or photo.
True size and scale: Because there is no perspective or distance-based shrinking, parts that are further back do not look smaller. A ten-centimeter line on the real object is always drawn as ten centimeters on the paper.
2D/3D CAD: it means using computer software instead of paper and pencils to create technical drawings.
2D CAD two dymensions
What it is: Digital drawing on a completely flat screen. It is exactly like drawing with your pencil and ruler, but using a mouse or keyboard commands.
What you create: separate, independent views (front, top, and side views) using flat lines.
The problem: If you change a measurement in the front view, the Top view does not change automatically. You have to fix every view manually.
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3D CAD three dymensions
What it is: Modeling a solid object inside a virtual 3D world. You build the object just like a piece of clay.
What you create: A single, realistic 3D model that you can rotate, look at from any angle, and even test for weight or strength.
The cool thing: The software automatically generates the flat 2D front, top, and side views for you! If you change the 3D model, all your 2D blueprints update instantly.
Famous Examples: SolidWorks, Tinkercad
FRONT/TOP/SIDE VIEWS
Front, top, and side views in technical drawing are called multiview projections. They show a 3D object as flat, 2D drawings from three different angles:
Front View: The most important view. It shows the front of the object and it´s the side that gives the most information.
Top View: What you see when looking at the object from directly above. In standard school drawings (Third-Angle), it is drawn directly above the front view.
Side View (Profile / Perfil): What you see from the side. The right-side view is drawn to the right of the front view.
FIRST AND THIRD ANGLE
First drawing and third drawing projections are the two international standards used to organize the front, top, and side views on a technical drawing sheet.
First angle projection:
Top View: You look from the top, but you draw it BELOW the front view.
Left Side View: You look from the left, but you draw it on the RIGHT side of the front view.
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DIMENSIONING: Is the process of adding size measurements, numbers, and thin lines to a technical drawing so that someone can create or build the actual object accurately.
Elements
Dimension Line: A thin, continuous line with arrowheads at both ends that shows the span of a specific measurement.
Extension Line: A thin line that starts with a tiny gap from the object's edge and extends out to meet the dimension line.
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