Tech Drawing (H)

eamoss

What did you think?

I messed it up so bad I really need to do well in paper II.

Q4 & Q7 Which I taught wud be two of my best question but I them messed up bad.

Feral Mutant

Went great for me. Did 1,3,4,5,6 and 7. The skew lines bit of the first question was kinda weird but I figured it out.

whassupp2

Overall I thought it was a tough but fair paper.

Q1a fine
Q1b fine. got 54 degrees for dihedral
Q1c i knew what to do but couldnt figure out how to do it. needed to get plane ade as trus shape. In the end it was quite easy. de is a true length in plan. I got it wrong however.
Q1d This was a big trick. D and E same heights. Couldnt do it first then returned and made a balls of it. Heard after that you were supposed to start in plan.

Q3a fine
Q3b fine
Q3c made a decent effort but dont know did i get it right.

Q5a fine
Q5b Got this fine but made the mistake of diving mathematically rather than technically. dunno will i lose marks.

Q6a fine
Q6b fine except i couldnt get point of contact of tangent.

Overall i'm happy. Tomorrows paper should be harder however.

Raphael

Thought it was a nice paper, I did 1,2,4,5 and 7

Feral Mutant: Aye, took me about 5 minutes to figure it out, then I was tempted to bang my head off the desk when I saw it. Q1 was obscenely easy.

whassupp2

Feral Mutant wrote:

Went great for me. Did 1,3,4,5,6 and 7. The skew lines bit of the first question was kinda weird but I figured it out.

Howdya have time for all them??

Feral Mutant

whassupp2 wrote:

Howdya have time for all them??

*shrug* Just got the questions done quickly and had time left over. My question 4 was kinda messy and I may have missed a point or two. Normally I wouldn't touch interpenetration *tee hee funny name* with a 20 foot pole, tbh I only did that one so I could say I did six questions.

Shark-69

Easy enough paper but i ****ed up the loci/cycloid Question......Q1 was easy...I started on this question.....after 20 mins i realised that i had the wrong line of intersection so i started again on a new sheet and got it all done correctly.....Q4-interpenetration was grand but took me 40 mins.......Solids in contact-Q3- was pretty straightforward but i got the wrong traces.....my traces went off the sheet because i used the centre of the cone B to swing an arc instead of swinging an arc from the point R...oh well **** it.....Then i should have spent the rest of my time on Q7 but did the stupid cycloid Q and drew a wrong locus with a loop in it instead of a dip or something..[according to my fellow students]..I did part a and b of 7 incase i got insufficient marks from the loci Q........

Gambra

We all thought this paper was a piece of piss. I messed up my interpenetration q a wee bit but still thought I got 70% percent. I guessed my plane directors in the solids in contact and couldn't get part (c) of Q1. I'm aiming for an A1 in this subject!!

Umiq88

Grand paper

would say i got full marks in q4 and q7 got the a part of q5 grand didnt attempt the b part and q3 was fairly ok altogether think i may have got 150-180 out of 200 not a bad result

hopefully paper 2 will suit me and i should get a b

Nichololas

Q1. Got a b and c alright. Didn't get time to go back over d though.

Q4. Took longer than usual to set it up so didn't quite get all the lines of interpenetration.

Q5. Part A was grand, forgot how to do b :F

Q7. Grand, full marks I think.

Overall I think I got a B on that. I don't like paper 2 as much so I hope I can at least keep up the B overall.

eamoss

Q.1 Fine but didnt really understand part C and part D was tricky you wer ment to start off in plan yea? EM 40
Q.3 Got it all done in 20mins taught it wud be my worst question but was ok. EM 30
Q.4 I spent too long settin it up and made a balls of it!! EM 20
Q.7 Feel like a tit for being soo stupid with that question EM 15

EM = Estimate Mark

Will have to do a lot better in paper II

Raphael

Q1 - Amazingly easy. Took me a sec to get d, but when I realised it twas a doddle
Q2 - Left this one till last, because the part c was a little iffy. Got it in the end using a locus though
Q4 - Handy enough, Visibility got a bit tricky right at the bottom elft of the plan though
Q5 - Pretty simple, glad I had my flexicurve. Looked a bit weird though.
Q7 - Simple enough, a&b were a doddle, c had a few bits that took me a ehile to figure out. Like how to get the sides of the pyramid in plan. Worked out fine though

Pretty sure I got the A1, might even be pushing 100% for the paper.

Funkstard

I did pretty well I suppose.

Q1 - Not sure if I got c) fully right. I just projected at 90degrees from DE in the plan and drew a 70degree angle from it to A. Realised after I should have gotten ADE as a true shape. Couldn't figure out d) until the very end when it was too late. I got the auxiliary drawn from the plan but that was all I had time for.
Q3 - I found it unbelievably easy. All the points of contact were on the side of the right cone so I literally had it done in 5 minutes. I was sure I had something wrong because I did it so fast. Still not so sure. Not too sure about my traces though.
Q4 - Took me absolutely ages but I think it's mostly right. I hadn't done of these in ages and quickly remembered why I didn't like them.
Q5 - Got a weird curve but so did everyone else. Logarithmic spiral was piss.

I had time to do the theorem question, but I couldn't get it started so I just left it and went back over stuff.

Really annoyed over Q1 c) and d) though.

whassupp2

Funkstard wrote:

Q5 - Got a weird curve but so did everyone else. Logarithmic spiral was piss.

Ya I got weird curve. How did u do the 4:5 ratio--- technically or mathematically???

totalmuppet

Did anyone do Q2 and if so did you get the shape out straight away without testing other possible solutions. Anyone else i've spoken to got this, me included, but it just seemed far too easy and I reckon there must be a fault in the question

Q1 - Piss, strike was DE
Q2 - Easiest theorem yet......I think
Q4 - Frustrating shape that just wouldn't work out for me
Q5 - Perfect in under 10 mins
Q6 - Except b2 simple, but even that wasn't hard

Overall, a great paper, probably pushing high 90's

whassupp2

This is similar to the curve i got for the loci question. Anyones any differenT??????

Raphael

totalmuppet wrote:

Did anyone do Q2 and if so did you get the shape out straight away without testing other possible solutions. Anyone else i've spoken to got this, me included, but it just seemed far too easy and I reckon there must be a fault in the question

Q1 - Piss, strike was DE
Q2 - Easiest theorem yet......I think
Q4 - Frustrating shape that just wouldn't work out for me
Q5 - Perfect in under 10 mins
Q6 - Except b2 simple, but even that wasn't hard

Overall, a great paper, probably pushing high 90's

I did Q2, but I'm not entirely sure what you mean

whassupp2: Yeah, looks kinda like mine. Had that big hooky bit.

sticky9cd

whassupp2 wrote:

This is similar to the curve i got for the loci question. Anyones any differenT??????

lol-honours td eh!!!:D
mine was the samee;)

totalmuppet

whassupp2 wrote:

This is similar to the curve i got for the loci question. Anyones any differenT??????

Couldn't load the image but if weird means that it had a sudden change of direction after the first 90 degrees of motion then its right because the point works its way along and back the AB curve

whassupp2

sticky9cd wrote:

lol-honours td eh!!!:D
mine was the samee;)

Ya i've always been known for my shaky hand when drawing curves.:D

whassupp2

totalmuppet wrote:

Couldn't load the image but if weird means that it had a sudden change of direction after the first 90 degrees of motion then its right because the point works its way along and back the AB curve

Yep. it curves around for a bit, then curls upward before swinging clockwise to the ground

Raphael

whassupp2 wrote:

Ya i've always been known for my shaky hand when drawing curves.:D

And that's why flexicurves are the best invention ever.

whassupp2

Raphael wrote:

And that's why flexicurves are the best invention ever.

Never used them and dont plan startin now. Are they the same as french curves???

sticky9cd

for Q1 D -did ye use the horizontal line in plan,and look at it as a point from the plan?? my traces on Q3 were realy far out. done **** in interpenatration cause when i done the 3rd view, the square based prism looked like really odd!!!

Raphael

Nope

Them thingies. You just bend it to get the curve that fits your points.

whassupp2

sticky9cd wrote:

for Q1 D -did ye use the horizontal line in plan,and look at it as a point from the plan?? my traces on Q3 were realy far out. done **** in interpenatration cause when i done the 3rd view, the square based prism looked like really odd!!!

The idea for 1d is that the line de is horizontal in elev. therefore its a true lenght in plan. a is on the plane ade. therefore a line from a to de must also run along the plane. You draw xy at parallel to de in plan. bring a to that view and using prtractor draw a line at 70 degrees to it.

whassupp2

sticky9cd wrote:

for Q1 D -did ye use the horizontal line in plan,and look at it as a point from the plan?? my traces on Q3 were realy far out. done **** in interpenatration cause when i done the 3rd view, the square based prism looked like really odd!!!

The idea for 1d is that the line de is horizontal in elev. therefore its a true lenght in plan. a is on the plane ade. therefore a line from a to de must also run along the plane. You draw xy at parallel to de in plan. bring a to that view and using prtractor draw a line at 70 degrees to it.

whassupp2

sticky9cd wrote:

for Q1 D -did ye use the horizontal line in plan,and look at it as a point from the plan?? my traces on Q3 were realy far out. done **** in interpenatration cause when i done the 3rd view, the square based prism looked like really odd!!!

The idea for 1d is that the line de is horizontal in elev. therefore its a true lenght in plan. a is on the plane ade. therefore a line from a to de must also run along the plane. You draw xy at parallel to de in plan. bring a to that view and using prtractor draw a line at 70 degrees to it.

whassupp2

Raphael wrote:

Nope

Them thingies. You just bend it to get the curve that fits your points.

never seen them before. thas technology for ya

Raphael

sticky9cd wrote:

for Q1 D -did ye use the horizontal line in plan,and look at it as a point from the plan??

Yeah, you just draw an auxiliary view with DE as a point, then join from there perpindicularly to AB. Get the point where it hits AB in plan, and because it was a true length in the auxiliary then the line is parallell to the X1Y1

Funkstard

Yeh that's the same curve I & all my class got. I'm usually good at the theorem, but I just couldn't get it started today. How did you start it?

And about the spiral, I don't know which way I did it...I got the first and second length, swung up to a 30degree line, swung it back down and repeated it, each length getting bigger each time

Feral Mutant

Raphael wrote:

Them thingies. You just bend it to get the curve that fits your points.

Some guys in my class have those 'cept they call it a jackerflex.

Raphael

Funkstard wrote:

Yeh that's the same curve I & all my class got. I'm usually good at the theorem, but I just couldn't get it started today. How did you start it?

And about the spiral, I don't know which way I did it...I got the first and second length, swung up to a 30degree line, swung it back down and repeated it, each length getting bigger each time

Area's of figures? Call the point outside the circle x. You know that the distance from |xC|.|xA|=|xD|.|xD| , which let's you get A and C

Now, if you go off at 20 degrees from A and C you can get O (angle at the centre = twice angle at the circumfrence. Draw the circle.

D you can get by swinging an arc length 120 from x and getting where it hits the circle.

You know the area of ABC is half ADC. since the base is common, that means the height is half. So half the distance from D to AC, and then draw a light line that distance from AC on the other side. Where it hits the circle on the right is B

Feral Mutant wrote:

Some guys in my class have those 'cept they call it a jackerflex.

A......jackerflex? They're clearly idiots, you;re going to have to kill them for the good of the human race.

Funkstard

Right I'll have to get it out now and try it again. The rest of it seemed fine, I just couldn't get it started & already had 4 questions done so I just left it

"You know that the distance from |xC|.|xA|=|xD|.|xD| , which let's you get A and C"

How do you know that? It doesn't say it's a similar triangle or anything..

sticky9cd

Raphael wrote:

Yeah, you just draw an auxiliary view with DE as a point, then join from there perpindicularly to AB. Get the point where it hits AB in plan, and because it was a true length in the auxiliary then the line is parallell to the X1Y1

yes - got that

Raphael

It's a formula about circles. Like the one with crossing over chords.

Edit: "If a secant and a tangent are drawn to a circle from an external point, the product of the secant and its external segment equals the tangent squared"

sticky9cd

this is what i got for q3

Funkstard

Oh right. Never learnt that! Haven't seen it in a pass paper either

Raphael

...it was in last years paper

Edit: There's another solution for last years, but it's also in '02 and '00 with no obvvious alternative solution.

Funkstard

I must have done it a different way 'cos I didn't use it doing that question.

whassupp2

sticky9cd wrote:

this is what i got for q3

A doesnt overlap with the cone and you left out the other cylinder.

Nichololas

Can anyone give me a quick run-down of dihedral angles and getting auxiliary points in perspective? (I missed the 3 classes when we did them. )

eamoss

Im prob the best person to be expaining this but anyway I will give it a go. Also I have very very bad english so try & make out what I am saying

dihedral angles
how to find D.A

Red Line = Draw a line which touches both sides of the roof

Green Line = Fold down the hip rafter

Then when the green line hits the red line come off perpendicular to the top of the hip rafter(shown by the blue line).

Then with ur compass using your two points(both ends of the blue line) bring it down till it hits the bottom of the rafter(purple line).

Then with the two points from the red line join them up with the line you just took down(yellow line)

The gray line is the d.a

Auxiliary V.P

Raphael

Hang on a sec, the blue line should be where the red line hits the base, shouldn't it? By the base I mean the other green line that you flattened the hip rafter around

Nichololas

What does folding down the hip rafter entail? I can't figure it out from the diagram.

eamoss

Raphael wrote:

Hang on a sec, the blue line should be where the red line hits the base, shouldn't it? By the base I mean the other green line that you flattened the hip rafter around

Whoops, yep ur right.

Enlil_Nick wrote:

What does folding down the hip rafter entail? I can't figure it out from the diagram.

Its basically just looking along so that you can see the true height of the hip rafter.

Raphael

Just rebatting it around.

Imagine the hip rafter as being a trap door that's open, what you're doing is pushing it so it falls closed

eamoss: oh good, was afraid I'd been doing it wrong ^^;

Nichololas

Oops, I get it now. I don't usually do it superimposed onto the plan also.

whassupp2

Cheers fo the info. I'll print that and learn it. By the way, did u draw them in MS Paint and how did you get them on screen without using an attatchment???

Raphael

www.photobucket.com, or somesuch

sticky9cd

whassupp2 wrote:

A doesnt overlap with the cone and you left out the other cylinder.

ya i drew it wrong but at least i know you realised what i had wrong. i done it right in the exam(i hope):D