Engineering Drawing Part I

Explore projection of a point in engineering drawing, constructing its front, top, and side views in the four quadrants using HP, VP, profile plane, and distances H, D, and F.

Explore drawing the projections of seven points on the ground line using 25 m projector spacing, with HP and VP, quadrants, and front and top views.

Construct projections for points P and Q, applying first and third quadrant rules, mark h and 40 below, and connect top and front views with a 90 mm projector distance.

Solve a two-point projection problem by determining how far point B lies behind the VP, using front and top views, a 45-degree top-view line, and a 75 mm projector distance.

Locate q in the first quadrant at 40 above hp and 30 in front of vp; draw projections and compute the 50 mm distance via auxiliary plane.

Compute the 60 mm distance for point a in the first quadrant from the auxiliary plane, yielding h = d and theta = 45 degrees for front and top views.

Explore projection of points in engineering drawing using the third quadrant and constructing front, top, and side views with distances 20 below HP and 40 from VP.

Explore how a two-dimensional figure revolved about an axis forms a double-napped cone, then slicing the cone with planes yields circle, ellipse, parabola, and hyperbola.

Explore conic sections by examining a double-napped circular cone, cutting planes, and the resulting outlines—ellipse, circle, parabola, and hyperbola—and their key properties, asymptotes, and generators.

See conic sections through a mathematical lens: ellipse, parabola, and hyperbola arise from the cutting plane’s angle with the cone axis; theta greater, equal, or less than alpha.

Explore eccentricity and its link to conic sections, learning how the focus, directrix, and vertex define ellipses, parabolas, and hyperbolas through constant distance ratios.

Learn the general method for ellipse construction using the focus-directrix ratio with eccentricity about 0.66, and note that the sum of distances to the two foci equals the major-axis length.

Learn ellipse construction with the oblong method, using a 125 by 75 mm rectangle and line division with compass arcs to produce a precise, tangential curve.

Master the concentric circles method to construct an ellipse from major and minor axes with a compass; draw vertical lines from outer circle and horizontal lines from inner circle.

The ellipse is defined by the primary property: the sum of distances from two fixed foci to any point on the curve is constant, equal to the major axis.

Learn the arcs of circles method to construct an ellipse by locating f1 and f2 from the major axis, and applying the put-and-cut technique with major and minor axis measurements.

Construct ellipse from foci 90 mm apart and minor axis 65 mm. Determine major axis length about 111 mm; apply concentric circles for half and oblong method for the other.

Construct a parallel ellipse 25 mm outside the original by marking points on the ellipse, drawing 25 mm arcs from these points, and drawing tangents to form the parallel ellipse.

Learn to identify ellipse problems from a sum of distances to renamed foci A and B, compute major axis PQ = 125, and construct the ellipse with arcs of circles.

Apply the general method for parabola construction using focus and directrix; locate the vertex 25 mm from the focus, and construct the curve with focus-centered arcs, yielding tangent and normal.

Learn to construct a parabola with rectangle and tangent methods through a practical ball-trajectory example, using a 75 by 45 rectangle, scale drawing, and reflection to form the curve.

Explore constructing a parabolic path using the rectangle method to plot a stone's trajectory from a seven-meter building toward the ground, using a one-metre-to-one-centimetre scale.

The lecture shows constructing a fountain jet's trajectory as a parabola using the tangent method, with a 60-degree exit angle and scaling eight meters to eight centimeters.

Explore the general method to construct a hyperbola from eccentricity greater than one, a focus-directrix distance of 50 mm, locating vertex and axis, drawing tangents, normals, and asymptotes.

Learn the difference property of a hyperbola: the constant difference of distances to two fixed points F1 and F2, and its relation to the ellipse's sum property.

Learn to construct a rectangular hyperbola through a given point using distances from two perpendicular lines, a ten-point method, and understand asymptotes as lines meeting the curve at infinity.

Construct a simple hyperbola through P with asymptotes along a and OB, given a 75-degree angle, using marked points, parallel lines, and a drafter.

Learn to construct a hyperbola by the arcs of circles method using foci A and B 50 mm apart and a constant difference of 20 mm, including asymptotes.

This lecture teaches two methods to construct the tangent and normal to an ellipse: a quarter-circle method with axis parallels, and a focus-based method using the angular bisector as normal.

Discover three methods to construct tangent and normal to a parabola using perpendiculars, parallel axis lines, and a focus–directrix angle bisector.

Use arcs of circles to construct the tangent to a hyperbola; connect P to F1 and F2, take the angular bisector of ∠F1PF2 as the tangent, then the normal follows.

Explore cycloidal curves, namely cycloid, epicycloid, and hypocycloid, generated by a point on a rolling circle, either outside or inside a directing circle. Learn construction techniques and tangents and normals.

Demonstrates cycloid construction from a rolling circle of diameter 50 (radius 25), tracing a circumference point through one revolution, with tangent and normal construction and notes on epicycloid and hypocycloid.

Construct a hypocycloid by tracing the locus of a point on a rolling circle inside a directing circle, using eight divisions, yielding a 102.8-degree angle. Then draw tangent and normal.

Construct the cycloid traced by a point on a 50 mm diameter wheel as it rolls half on a horizontal base and half on a vertical wall, with step-by-step construction.

Explore the hypocycloid where the directing circle's diameter is twice the rolling circle's, proving the curve becomes a straight line through a detailed construction.

Explore how a rolling circle generates cycloid, inferior trochoid, and superior trochoid, by tracking points on the circumference, inside, and outside the circle.

Discover how to construct an inferior trochoid by tracing a point on a rolling 40 mm diameter circle, using eight divisions and arcs to plot P1 to P8.

Construct the superior trochoid in engineering drawing part i by rolling a 40 mm disk, marking eight points 30 mm from the center, and tracing the locus.

Explore the involute curve by winding a tight inelastic string around a circle, using a coin demonstration, and analyze three cases based on string length relative to pi D.

Compute the circle circumference and compare it to a 165 mm elastic string wound around a 50 mm disk, showing how the string exceeds the circumference and guides tangents.

Construct the circle's involute by winding a 165 mm string around a 50 mm diameter disk and tracing point p as the string length exceeds the circumference.

Construct the involute of a circle when string length is less than pi d, using eight-part division, a 25 mm radius, and compass arcs to locate point P.

Explore involute construction for a rod rolling on a semicircular plate, tracing ends P and Q to form the curve using four divisions and compass arcs.

Explore the concept and construction of scales in engineering drawing, including reducing, enlarging, and full scales, and learn about representative fractions and unit conversions.

Learn to construct a plane scale with two units using a 1:4 representative fraction. Shrink five decimeters to 12.5 cm, then divide into five equal parts with a drafter.

Construct a plain scale by deriving rf from 1 ft = 1.5 in, plot a 15.2 cm length, and mark feet and inches up to four feet.

Construct a diagonal scale for three units—yards, feet, and inches—up to four yards, using rf 1/32 and centimeter conversions, with the diagonal transferring divisions.

Construct a diagonal scale for miles, furlongs and chains using rf 1/5068, up to five miles, converting to centimetres and dividing into miles, furlongs, and chains.

Derive the representative fraction from map area ratios and construct a diagonal scale for kilometers, hectometers, and meters in engineering drawing.

Learn to construct comparative scales in plain and diagonal forms, for miles and kilometers, using a common representative fraction to translate drawing lengths into real map distances.

Construct a vernier scale with red 10 mm and yellow 11 mm divisions, and use rf 1/25 to read up to four meters, measuring 2.39 m and 0.91 m.

Explore scale of chords to measure angles on circle with compass constructions to bisect and trisect angles, and relate chord lengths to angles like 10°, 20°, 30°, and 40°.