Nearside and offside: Why?

[kambites]

doogz said:

kambites said:

Yes, but specifically with the X axis pointing right and the Y axis pointing up. I'd never draw a number-line with numbers increasing to the left, it just feels completely unnatural (again, for no particular reason beyond convention).

So specifically with the positive y axis 90 degrees counter clockwise to the positive direction of the x axis. Sort of exactly like we use here.

I don't really see a reason to distinguish between X and Y Axis, they're just interchangeable names to me. I'd happily draw a graph with X pointing up the page and Y to the right; or with Y pointing up the page and X to the right. Either way, one would always be upwards and one always right.

In fact I don't think I've ever drawn a graph with the axis labelled "X" and "Y" in my life. If I have, it was coincidental not because they have any special meaning beyond any other symbol used to denote a variable.


I suppose if I was in your situation I would naturally have used three symbols (call them X Y and Z if you like) for increasing to the right, forwards, and upwards from the driver's seat and not even thought about which was which. I suppose it doesn't matter as long as everyone knows what you're talking about though, as with most conventions.

Edited by kambites on Thursday 17th January 15:01

[V8mate]

kambites said:

Out of interest, which side would the Germans have mounted their horses from?

The rear, in the videos I've seen.

[Captain Muppet]

kambites said:

Out of interest, which side would the Germans have mounted their horses from?

The left, assuming that the majority of their sword using horse riders were right handed.

Sadly nearside is defined as "the side of a vehicle nearest the kerb" rather than the horse usage which just means the left side of the horse.

Obviously the vehicle definition is mental, especially if applied to a horse drawn carriage used in a country that drives on the right, in which case the nearside of the horse would be on the offside of the vehicle, even though all of their lefts would be on the left.

[Captain Muppet]

V8mate said:

kambites said:

Out of interest, which side would the Germans have mounted their horses from?

The rear, in the videos I've seen.

[kambites]

doogz said:

I don’t get your point. You’d never use a right hand coordinate system? Apart from the countless times you have?

I've never even heard of the right hand coordinate system.

If I'm understanding you right (which I might not be), you seem to be saying that X and Y are somehow special, that you can look at an unlabelled graph (numbers but no axis names) and say "that's the X axes and that's the Y axis". That, to me, is a complete nonsense; they're just arbitrary names.

[HustleRussell]

Captain Muppet said:

HustleRussell said:

I'm the only one here who actually likes 'N/S' and 'O/S' then? seems pretty natural to me, although when I have used them in conversation it almost invariably results on 'which side is that?' sort of questions. I put that down to their stupidity rather than my excessive car geekery though.

Excellent, so which side is the nearside of a GDM but UK registered E30 M3 parked facing on-coming traffic in Paris?

Also which is the neaside of two consecutive chassis numbered E30 M3s one of which is GDM and the other of which is UKDM? I'm pretty sure the nearside of the UK one is left, and the German one is right.

Which would mean that you'd need to order a nearside door from Germany to replace your offside door in the UK. Although as soon as you unbolt it from the car it's just a right hand door, because the whole nearside/offside thing can't cope with parts, only cars when parked next to a kerb with a clearly defined side of the road for normal travel.

Of course the label on the door would say "R" on it, because BMW are a global company that don't use horse terms to needlessly double their stock of spare parts.

It's odd that no one at all says that the UK drives on the nearside, we all drive on the left.


Although as you say, I may just be too stupid to understand the thing.

Both of my cars are UKDM and both of them live in the UK. I source all my parts by part number. It's literally a non-issue for me

Of course if you are driving a GDM but UK registered E30 M3 in Paris, you are unlikely to be shopping for spares for it at the same time (hopefully!)

[GroundEffect]

kambites said:

doogz said:

I don’t get your point. You’d never use a right hand coordinate system? Apart from the countless times you have?

I've never even heard of the right hand coordinate system.

If I'm understanding you right (which I might not be), you seem to be saying that X and Y are somehow special, that you can look at an unlabelled graph (numbers but no axis names) and say "that's the X axes and that's the Y axis". That, to me, is a complete nonsense; they're just arbitrary names.

You need rules otherwise you can't work coherently in a group. Imagine in Doogz' case of building a ship or on my smaller scale of building a car, you have loads of engineers working within the same digital, and physical, environment. If you didn't all use the same vehicle coordinates and use the same rules you'd have one fked up situation.

Oh and to address your question of them being arbitrary - if you assign the X axis and your system is using the right-hand rule then you have automatically assigned the rest of your axes.

[kambites]

GroundEffect said:

kambites said:

doogz said:

I don’t get your point. You’d never use a right hand coordinate system? Apart from the countless times you have?

I've never even heard of the right hand coordinate system.

If I'm understanding you right (which I might not be), you seem to be saying that X and Y are somehow special, that you can look at an unlabelled graph (numbers but no axis names) and say "that's the X axes and that's the Y axis". That, to me, is a complete nonsense; they're just arbitrary names.

You need rules otherwise you can't work coherently in a group. Imagine in Doogz' case of building a ship or on my smaller scale of building a car, you have loads of engineers working within the same digital, and physical, environment. If you didn't all use the same vehicle coordinates and use the same rules you'd have one fked up situation.

Oh and to address your question of them being arbitrary - if you assign the X axis and your system is using the right-hand rule then you have automatically assigned the rest of your axes.

OK good, so I do understand what he's saying, I'd just never even come across the concept of such a standardisation before, although I can understand why it's required. And it still feels back-to-front to me.

As I said, I think it's just an "engineer" vs "mathematician" thing. A mathematician would look at it and say it doesn't make the blindest bit of different what axis points in what direction because to a mathematician the whole concept of "direction" is arbitrary. That probably doesn't work so well when your'e designing an aircraft carrier, though.

Edited by kambites on Thursday 17th January 15:25

[Captain Muppet]

This is how engineers flip people off:

[kambites]

doogz said:

kambites said:

I've never even heard of the right hand coordinate system.

If I'm understanding you right (which I might not be), you seem to be saying that X and Y are somehow special, that you can look at an unlabelled graph (numbers but no axis names) and say "that's the X axes and that's the Y axis". That, to me, is a complete nonsense; they're just arbitrary names.

I’m not suggesting the letters “x” and “y” are somehow special, but you seem to think it’s very odd that we use ‘left’ as positive. We don’t. Positive is along it’s axis, which happens to be 90 degrees counter clockwise from the axis defined as x, or our longitudinal axis.

It’s no different from drawing 2 perpendicular lines on a piece of paper, as you say, and labelling the bottom one ‘x’, and the one that runs up the page ‘y’. There is no ‘left’ involved. There’s a set of axes that have defined positive directions, that are all perpendicular to each other. If you follow the x axis on this:



Then move to a positive y value, you're moving to the 'left' of the x axis. Exactly the way we work. I just can't see what you find so strange about that. To you, a positive "y" value would be down the way? To the 'right' of the x axis?

You’re a mathematician, and you’ve really never heard of a right hand coordinate system? That’s a bit strange.

The term "counter-clockwise" makes no sense to me from a purely mathematical point of view either because, conceptually speaking, a graph can be viewed equally validly (and indeed logically identically) from either side of the plain it's projected onto.

And no, I've never come across the term. In fact I'm not sure I've ever come across the term "coordinate system" or indeed even heard the word "coordinate" used in a purely mathematical context.


Why is it called the "right hand" coordinate system?

Edited by kambites on Thursday 17th January 18:39

[Mr2Mike]

Captain Muppet said:

Excellent, so which side is the nearside of a GDM but UK registered E30 M3 parked facing on-coming traffic in Paris?

The location of the steering wheel, or how it's parked makes no difference. The nearside of your M3 will be the left hand side in the UK (viewed sitting facing forwards within the car), and the right hand side on the Continent.

[Toltec]

Captain Muppet said:

you can't draw a sword fixed to your shoulder that's longer than your arm.

You can, but it needs a split sided scabbard.

[Captain Muppet]

doogz said:

By posting links to images that we're not allowed to see?

I must admit, I'm slightly curious as to what it was, maybe even mildly annoyed that I can't see it, but that's about it.

:disappointedlinkdidntwork:

It was a CAD manikin hand showing the right hand rule.

[bqf]

Isn't nearside the drivers side?

[Captain Muppet]

bqf said:

Isn't nearside the drivers side?

It depends, hence my hatred of the stupid naming convention.

It's the driver's side of a LHD car in the UK.

Basically the nearside is the same as the side of the road you drive on in that country (although the definition is really badly worded so even that isn't always true), so with a normal RHD car in the UK it's the left. Unless you go on holiday to France, in which case it's the right.

It's anyone's guess which side is the nearside on a ferry, which is why it's so important not to to crash on a ferry as no one will be able to fill out an insurance form correctly.

I always use "left" and "right" because anyone who can't get that right is going to have to be so stupid they spend quite a bit of their life with painful feet trying to work out why their gloves don't fit. Plus "left" and "right" are the international standard for automotive engineering.

[kambites]

doogz said:

kambites said:

The term "counter-clockwise" makes no sense to me from a purely mathematical point of view either because, conceptually speaking, a graph can be viewed equally validly (and indeed logically identically) from either side of the plain it's projected onto.

And no, I've never come across the term. In fact I'm not sure I've ever come across the term "coordinate system" or indeed even heard the word "coordinate" used in a purely mathematical context.


Why is it called the "right hand" coordinate system?

Edited by kambites on Thursday 17th January 18:39

Seriously?

Google it. There's more than likely a wikipedia page on it, that will give you the general idea.

Hold out your thumb, fore finger, and middle finger of each hand, perpendicular to each other, consider the directions I mentioned were positive in the global coordinate system we use un here, and figure out why it's a right hand system, and not a left hand system.

Ah, that makes sense!

Mind you, it does depend on which way up you put your hand. If you rotate it palm-up, you get the directions that feel natural to me.

[kambites]

bqf said:

Isn't nearside the drivers side?

Nearside is the side nearest the kerb (if you're on the correct side of the road, obviously). Is it a bloody useless term because it means different things in different places.

Left and right are easiest, even if they are slightly ambiguous, and if you want concrete definitions Port and Starboard are perfect adequate existing terms.

[kambites]

doogz said:

kambites said:

Ah, that makes sense!

Mind you, it does depend on which way up you put your hand. If you rotate it palm-up, you get the directions that feel natural to me.

Or instead of rotating your right hand, use your left hand. Forefinger is "X", middle finger is "Y", thumb is "Z"

Indeed, gives you exactly the same set of directions.

[busta]

Nearside and offside are simply names for a cars left and right side. We always see left and right from the same perspective, so giving a separate name to the cars left and right sides allows us to easily differentiate what we are saying from our own perspective. It's also easier than saying 'the cars left hand side' or 'to the left as you are sat in the drivers seat'.

When stood at the front of a car, peering into the engine bay diagnosing a cracked linear-rotating static oscillator, using left and right is confusing but nearside and offside always makes sense.

Compare identifying the left-most spark plug of a transverse engine to identifying the nearside spark plug. The first leads to some confusion and mental images of the whole car spinning is free space, the latter is very straight forward.

[kambites]

Plus to identify NS/OS you need to know either which side the steering wheel is on or which country you're in. One of them is tricky to tell from under the bonnet and the other is impossible (although you'd probably know anyway). If I'm talking to an American about my car and he uses the term "offside", which does he mean?

Port and Starboard would be much better terms than either because they are fully consistent and fully defined.

Edited by kambites on Friday 18th January 09:34