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## TECH 104 – Technical Graphics Communication

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**TECH 104 – Technical Graphics Communication**Introduction to Engineering Graphics Communication**Development of Engineering Graphics**Multiview Drawings Francesca (1420-92) Cartesian Coordinates Descartes (1596-1650).**What you will learn**• Visualization • Graphics Theory • Standards • Conventions • Tools • Applications**The “Language”**TECH 104 – Technical Graphics Communication Lines may be defined as……. 1. The shortest distance between two points 2. The geometry created by the intersection of two planes or surfaces 3. A set of points organized that have length and direction, but no thickness**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Parallel lines will always maintain the same distance from each other throughout their entire length, and NEVER touch!**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Non-parallel lines do not maintain the same distance from each other throughout their entire length, and may either touch, or eventually cross each other.**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Perpendicular lines are at 90 degrees to one another.**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Intersecting lines cross each other at any angle.**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Tangent lines are created when: 1. A curved and straight line meet, and…. 2. The two lines intersect at only one point, and…. 3. A smooth transition into one line can be generated.**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Lines will appear as edges when there is an intersection of two planes or surfaces.**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Tangent conditions may appear in both 2D and 3D geometry…. Figure A shows a tangent being created at Point C Figure B shows Tangent F being identified as the intersection point between the 2 circles.**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Here we can see that Line VT is lying tangent to the cone.**TECH 104 – Technical Graphics Communication**Lines come in all types and shapes: Can you explain why Example A is tangent, but Example B is not??**TECH 104 – Technical Graphics Communication**Circles are considered the most perfect form geometric shape. All circles are made up of many parts…**TECH 104 – Technical Graphics Communication**A parabola’s shape can be generated from a 3D cone and 2D plane…. Notice that the parabola’s shape is symmetrical (mirror image of itself), and that it has a focus point inside the arc of the line. The cutting plane is always parallel to the slope of the cone.**TECH 104 – Technical Graphics Communication**Parabolas have many engineering uses and shapes…. As the shape of the curve of the parabola changes, it allows for more diverse applications.**TECH 104 – Technical Graphics Communication**The ellipse is generated in much the same way as the parabola…. Notice that the ellipse’s shape is symmetrical (mirror image of itself), like the parabola. However, the ellipse has no focus point identified inside the arc of the line, and the cutting plane is NOT parallel to the slope of the cone.**TECH 104 – Technical Graphics Communication**A circle may appear as an ellipse when the object is not perpendicular to the line of sight. While the circle’s geometry remains true shape and size, our view of its shape appears more oval as the object is rotated from its 90 degree position.**TECH 104 – Technical Graphics Communication**Lines can be set at angles to points or other lines… Lines set at angles help us understand the relationship of other lines, or the geometry’s position in space.**TECH 104 – Technical Graphics Communication**Quadrilaterals have two main characteristics: • They are CLOSED entities, • 2. They have 4 sides.**TECH 104 – Technical Graphics Communication**Polygon means “many sided”: Most polygons have names based on the number of sides they have.**TECH 104 – Technical Graphics Communication**2D and 3D Space: Let’s take a few minutes to see how lines and points are used to organize space…..**TECH 104 – Technical Graphics Communication**If we take the centre of the universe as our home position (X=0 and Y=0) , we are able to map out the coordinate vertices of any object from that point and assign them addresses so they may be easily located.**TECH 104 – Technical Graphics Communication**However, as the universe is not 2-dimensional, we must take into consideration a 3rd axis (Z) that represents its volume.**TECH 104 – Technical Graphics Communication**Since the computer ALWAYS remembers that its home is (0,0,0), we may locate any point in space, or on a 3D model, by referencing home.**TECH 104 – Technical Graphics Communication**Each point on a 3D model has its own address in space that is designated by an X, Y, & Z value. Here we can see the address of each vertex. Example: (4, 3, 0)**TECH 104 – Technical Graphics Communication**Next Week: Sketching, Text, and Visualization