DCG Before/After

kingcobra · 18-06-2013 2:16pm

For embankments towards the road. I prefer to think of the circle of the tadpole as a spring of water and then the stream of water from it flows down the hill.

Our teacher told us that they were sperm :pac:

Thataone · 18-06-2013 2:27pm

Slightly unrelated but was just looking through the SEC 2012 stats...
Only 435 girls sat the paper compared to 3369 guys. However approx 16% of those girls got As compared to 14% of guys.
Statistically, things are looking up for me :P

Leaving Cert Student · 18-06-2013 2:35pm

Last years geological geometry q was quite strange... id be screwed if something similar came up this yr!

Leaving Cert Student · 18-06-2013 4:21pm

Is the method of loci on our course? Also is the only things they an ask for geo geom. profiles, roadworks (rising and falling) and then dip, strike and thickness?

Thataone · 18-06-2013 4:30pm

Leaving Cert Student wrote: »

Is the method of loci on our course? Also is the only things they an ask for geo geom. profiles, roadworks (rising and falling) and then dip, strike and thickness?

Never heard of method of loci

but don't think it's on the course.

Leaving Cert Student · 18-06-2013 4:57pm

Cheers, and when a question asks: A plane director for the elements AD and BC is positioned so that it contains the point B. Draw the traces for this plane director.

Is there a general approach to this question? Like say I have two skew lines AD and BC, what do I need to do to get this plane director containing point b and what exactly does it mean to "contain point b".. Cheers to anyone who can help!

Thataone · 18-06-2013 5:08pm

Leaving Cert Student wrote: »

Cheers, and when a question asks: A plane director for the elements AD and BC is positioned so that it contains the point B. Draw the traces for this plane director.

Is there a general approach to this question? Like say I have two skew lines AD and BC, what do I need to do to get this plane director containing point b and what exactly does it mean to "contain point b".. Cheers to anyone who can help!

Not sure if this is what you mean but I found this earlier today...
http://www.t4.ie/DCG_Round_9/dcg_worksheets_1/Structural%20Forms/Structural%20Forms%20Solutions.pdf

Page 14 has a bit about plane directors etc. Not sure about if it contains point b etc but it's all I could come up with when I was trying find something similar before.

Daniel7740 · 18-06-2013 5:08pm

Anyone know of a video that shows how to get auxiliary vanishing points for perspective ?

Thataone · 18-06-2013 5:11pm

Daniel7740 wrote: »

Anyone know of a video that shows how to get auxiliary vanishing points for perspective ?

Leaving Cert Student · 18-06-2013 7:06pm

anyone have mock 2013 Marking scheme?

ILoveDance · 18-06-2013 7:38pm

Wow im screwed

anyone think axonometric is coming up?

ILoveDance · 18-06-2013 7:41pm

Thataone wrote: »

Slightly unrelated but was just looking through the SEC 2012 stats...
Only 435 girls sat the paper compared to 3369 guys. However approx 16% of those girls got As compared to 14% of guys.
Statistically, things are looking up for me :P

Yaayyyy

SORTED

Leaving Cert Student · 18-06-2013 7:42pm

ILoveDance wrote: »

Wow im screwed
anyone think axonometric is coming up?

it could do! Probably will be on either A or B alright, it is a handy enough question I find

ILoveDance · 18-06-2013 7:48pm

Leaving Cert Student wrote: »

it could do! Probably will be on either A or B alright, it is a handy enough question I find

ya hopefully!!

Leaving Cert Student · 18-06-2013 7:51pm

ILoveDance wrote: »

ya hopefully!!

How do you know which axis to put the elevation, plan and end view on though? I take it the plan is always on the bottom but can the other two be interchanged?

Thataone · 18-06-2013 7:53pm

Leaving Cert Student wrote: »

How do you know which axis to put the elevation, plan and end view on though? I take it the plan is always on the bottom but can the other two be interchanged?

It depends on what you've to draw really, *think* in some cases you've to draw them in a certain way to get all the detail etc but not 100% sure.

ILoveDance · 18-06-2013 7:56pm

Leaving Cert Student wrote: »

How do you know which axis to put the elevation, plan and end view on though? I take it the plan is always on the bottom but can the other two be interchanged?

Im pretty sure the elevation goes on the left (:

Leaving Cert Student · 18-06-2013 7:59pm

Thataone wrote: »

It depends on what you've to draw really, *think* in some cases you've to draw them in a certain way to get all the detail etc but not 100% sure.

Sometimes the XYZ axes are in different places, do they matter really? Like is the order they are in important or does it come down to drawing it the way it needs to be drawn?

Thataone · 18-06-2013 8:03pm

Leaving Cert Student wrote: »

Sometimes the XYZ axes are in different places, do they matter really? Like is the order they are in important or does it come down to drawing it the way it needs to be drawn?

For the XYZ axes, as long as the angles in between each match the ones given, surely that means they'd be drawn the way it needs to be drawn?

TBH I'm not really sure, I've always just gone with using the angles given between the axis and then from there putting in the rest of the draw (eg plan, elevation etc) as required.

mikeyod123 · 18-06-2013 8:11pm

anyone have any links for any mocks that might be online?

noelf918 · 18-06-2013 8:14pm

on 2012 Qb-3, http://www.examinations.ie/archive/exampapers/2012/LC562ALP015EV.pdf
how do you get the height of h?

bigt132 · 18-06-2013 8:18pm

Hey I think someone asked something about this question earlier but for the 2010 geologic geometry question does anyone know where the distance of 150mm was taken from to find the centre of the cone (for road rising 1 in 30 from B to C) Would it just be 150 from B or 150 horizontally from the contour line of height 60? I tried both of those but the placement of the cone looks a bit off to what it is in the solution... The solution is on pg18 on the link below..
http://www.examinations.ie/archive/markingschemes/2010/LC562ALP000EV.pdf

Thanks to anyone who can help!

Leaving Cert Student · 18-06-2013 8:20pm

bigt132 wrote: »

Hey I think someone asked something about this question earlier but for the 2010 geologic geometry question does anyone know where the distance of 150mm was taken from to find the centre of the cone (for road rising 1 in 30 from B to C) Would it just be 150 from B or 150 horizontally from the contour line of height 60? I tried both of those but the placement of the cone looks a bit off to what it is in the solution... The solution is on pg18 on the link below..
http://www.examinations.ie/archive/markingschemes/2010/LC562ALP000EV.pdf

Thanks to anyone who can help!

150 from B, but you step the radius off from the edge of the road not the centre, ya get me? That should be it anyway!

mikeyod123 · 18-06-2013 8:22pm

noelf918 wrote: »

on 2012 Qb-3, http://www.examinations.ie/archive/exampapers/2012/LC562ALP015EV.pdf
how do you get the height of h?

you project of the line of intersection and you get 4 points and the true length of line of intersection. now project parallel to line of intersection and you get the dihedral angle with the points ab, d and f. now if you take the points e and c from your plan and mark the height you can see where they hit the dihedral angle and then bring that back to where the true length is and you have height h.

very long and probably confusing sorry :P

Thataone · 18-06-2013 8:24pm

noelf918 wrote: »

on 2012 Qb-3, http://www.examinations.ie/archive/exampapers/2012/LC562ALP015EV.pdf
how do you get the height of h?

What I did:
look along DA in plan to find true length of BCDA. (Get heights for D,A,B from elevation. As you've brought C from plan (parallel to DA), the point where this line intersects BDA gives you the true height of C. You can then mark it in elevation.

I'm sorry it's not explained well, I can upload my answer either if that helps?

Barster · 18-06-2013 8:25pm

noelf918 wrote: »

on 2012 Qb-3, http://www.examinations.ie/archive/exampapers/2012/LC562ALP015EV.pdf
how do you get the height of h?

Hi , The Line D-A is parrallel to C-E so in plan just draw a line from C parrallell to D-A and where it cuts the Line AB in plan project it up . Where that point cuts the line AB in Elevation just horizontal line across from there is the height H

Just another alternative way of doing it there.

Jw has anybody any tips for the intersecting solids q's? they've come up the last few years and my teacher never covered them , frantically trying to grasp them atm , its finding the lines of interpenetration and knowing what cuts to use thats confusing me? help?

ConorIsCool18 · 18-06-2013 8:30pm

I really struggle with dcg theory and I was wondering if theres any sites or anything yous could shoe me that could help? what topics should I look over? had a **** teacher so that F'ed me over, I did a good project so kinda just hoping to do decent in this and get a c3? please help

Barster · 18-06-2013 8:35pm

ConorIsCool18 wrote: »

I really struggle with dcg theory and I was wondering if theres any sites or anything yous could shoe me that could help? what topics should I look over? had a **** teacher so that F'ed me over, I did a good project so kinda just hoping to do decent in this and get a c3? please help

T4.ie is a good one!
Youtube has a bit of stuff if your looking too!

Em For B try and cover , Axonometric, Perspective, Elipses, Intersecting Planes, Intersecting solids too if ye can!

And Section C depends on what you've studied , I do road geometry and surface geometry myself ! hope that helped

noelf918 · 18-06-2013 8:48pm

Thataone wrote: »

What I did:
look along DA in plan to find true length of BCDA. (Get heights for D,A,B from elevation. As you've brought C from plan (parallel to DA), the point where this line intersects BDA gives you the true height of C. You can then mark it in elevation.

I'm sorry it's not explained well, I can upload my answer either if that helps?

mikeyod123 wrote: »

you project of the line of intersection and you get 4 points and the true length of line of intersection. now project parallel to line of intersection and you get the dihedral angle with the points ab, d and f. now if you take the points e and c from your plan and mark the height you can see where they hit the dihedral angle and then bring that back to where the true length is and you have height h.

very long and probably confusing sorry :P

Barster wrote: »

Hi , The Line D-A is parrallel to C-E so in plan just draw a line from C parrallell to D-A and where it cuts the Line AB in plan project it up . Where that point cuts the line AB in Elevation just horizontal line across from there is the height H

Just another alternative way of doing it there.

Jw has anybody any tips for the intersecting solids q's? they've come up the last few years and my teacher never covered them , frantically trying to grasp them atm , its finding the lines of interpenetration and knowing what cuts to use thats confusing me? help?

thank you to all of you, to thataone, nah it's fine, i get it, thanks.

ulty77 · 18-06-2013 9:31pm

Okay, I'm doing OL and its easy but I never really learned how to do geological geometry or perspective drawing. Any advice?

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