Layout of the Paper

Section A: 4 short questions on the Core topics, 20 marks per question, marked out of your best 3. Attempt all four.

Section B: 3 long questions on the Core topics. 45 marks per question, marked out of your best two. Read all three, do the two you are most confident on, if you have time at the end of the exam then attempt the third.

Section C: This section has 5 optional areas on Applied Graphics but you will only be marked on two of these. The areas covered are Structural Forms and Geological Geometry. Do not waste time attempting another question in this section.

The exam is 3 hours long which allows for around 35 minutes for each of the long questions and another 35 minutes for all of the short questions in Section A.

Make sure your sets are fully equiped before the exam.

Core Topics

Orthographic and Auxiliary Projection

Most questions on the course are given in an orthographic (ele, plan and end ele). Auxiliary elevations have come up as a long question the last few years. Draw the given ele and plan and then project your out from the plan to get your auxiliary. Heights for the auxiliary are always got from the elevation. (Page 34-44)

Solids in Contact

Know how to find points of contact in plan and elevation (page 83-84)

How to rotate spheres, cones, cylinders to the side of an object, bring them down and find them in their correct position in plan. (page 85-93)

Axonometric, Dimetric and Trimetric

Set up the axes as given in the question. Draw a level line, project and get the semi circle to allow you to set up the plan. Do similar for elevation or end elevation. Look at the 3D view given in the question to decide which elevation to draw and the direction the plan is drawn. If you get this wrong the object could end up facing in the wrong direction. Circles and curves are got by dividing up 60/30 and projecting the individual points to the middle to get the freehand curve (page 137-151).

Perspective

Gettiing the plan drawn, finding the spectator, picture plane, ground line, horizon line and vanishing points will get you nearly half the marks in this question.

Join outer parts of plan to the spectator, bisect this angle to get the line of vision, go 90° to this through whatever point given in the question to get the picture plane.

Go parallel to the edges of the plan from the spectator till it hits the picture plane and project up 90° to the picture plane to the horizon line to give the vanishing points. 

Heights can only be marked off when its touching off the piture plane. If it doesn't touch the picture plane then you need to continue the line/edge on till it does hit the PP, bring it up and mark the height off on that line, vanish it back to collect the point you were looking for.

Remember that all points have to go be joined from the plan to the spectator and brought up from where that its off the picture plane. 

To get curves in perspective you need to divide up the circle/curve 60/30 and find the points individually (page 169)

Conic Sections

Parabola - Eccentricity is equal to one which means the line of ecc. is always 45°.

Ellipse - Eccentricity is less than one so the line of ecc. is any angle less that 45°

Hyperbola - Eccentricity is greater than one so the line of ecc. is any anlgel greater than 45°

 

Eccentricity method is done the same way on all three sections. Ecc = PF/PD (See page 191)

Remember that 45° line from focus to the line of ecc. and straight down from there will give the vertex.

Double Hyberbola is drawn using a different method (page 211). The transverse axis goes from vertex to vertex. Remember the rule PF1-PF2 = transverse axis.

Learn the properties common to all conics (page 219-221)

Solids cut by Oblique Plane

Set up the ele and plan. Draw the traces. Project up along the horizontal trace to get an auxiliary view showing the cutting plane. Use this view to find the points needed to finish the plan. (page 234-239) 

Rotate the points from the auxiliary to get the true shap of the cut surface out 90° from the plan. (page 240-241)

Get the traces of a plane by continuing on the edges in both plan and ele to find the traces. (page 243)

Interpentration

On basic questions, intersection points can be got by using method like Limits, Radial Elements, Horizontal and Vertical sections. (page 274-283). Questions like these generally tend to come up in the short questions.

Developments

Developments are the opening out of an 3D object to a flat 2D shape. (page 297-304) 

An envelopment is the opposite of a development, given the flat shape and you have to draw the 3D shape. (page 309-329)

Applied Graphics

Structural Forms

This has two main parts, the hyperboloid of revolution and the hyperbolic paraboloid.

Hyperboloid of Revolution - Know how to draw the curve in elevation by drawing the asymptote in plan and ele and finding the points from that (page 215).

Hyperbolic Paraboloid - Divide up the edges to get the elements needed. Project these elements to all view and they will produce the curves needed. Know how to take a section view along a line. (page 218-220).

 

Geological Geometry

There are two main topics in this section, road geometry and mining geometry.

Road Geometry - You will have to know how to get the profile along a given line and you will have to know how to get cut and fill for a level road.

To get the profile, bring up all the contour lines where they hit off the line and mark off the height of the contour in elevation. This will give the profile along that line.

If you are cutting then the level of the road is below the contours on the map. If you are filling then the level of the road is above the contours on the map.

For a level road you come out parallel to the side of the road. The distances you come out is determined on wheither you are cutting or filling and what ratios there are for them. The ratio given is always multiplied by the intervals of the ground contours (normally 5m).

Mining Geometry - Know how to get the dip, strike and thickness the traditional method by using the elevation and the level line method (page 263,270-275)

These can also be found just in the plan by dividing the line between the highest and lowest of the three points. It is divided into the number of intervals there are between these two points. (eg. 80 and 55 have 5 intervals of 5m between them so the line would be divided into 5 parts). The other point is then joined to its corresponding height on the divided line to give the strike line. The dip and thickness are found by looking along this strike line and taking an auxiliary (page 270-275)