1st Angle versus 3rd Angle projection

[jcapriotti]

Round 1, Fight!

[MJuric]

What difference does it make? They're the same thing. The only time it is a problem is when you are working with both regularly and someone forgets to look at the title block and or someone doesn't indicate which projection it is on the title block.

I really don't care which one, I only wish we would decide to use one or the other rather than both.

[jcapriotti]

Our global parent is trying to get us to switch to 1st. Very difficult as we make mechanical products in an architectural world. A lot of retraining to come and many of our US based vendors and customers present a further challenge.

I don't mind changing how we do something but 1st angle makes no logical sense. I see how and why it was developed but it appears to be more of a philosophical decision made by Europe rather than a practical decision.

[MJuric]

I don't mind changing how we do something but 1st angle makes no logical sense. I see how and why it was developed but it appears to be more of a philosophical decision made by Europe rather than a practical decision.

I really don't see any difference logically. it's just a choice of which way you flip the part. Flip the part up or roll the part over.

In the real world 1st angle is actually easier. If you have a 100lb block and flip it, you are doing first angle :-)

[mike miller]

It's just like the age-old imperial/metric argument. It gets no one anywhere and just ruffles feathers.

"There are only two kinds of countries; those that use metric and those that put a man on the moon."

"Metric is so much easier to use."

"Thousandths are smaller than millimeters so imperial is more accurate."

"Metric is better because the best countries use it."



And it ultimately ends in: "Metric leads to socialism. Just look at the socialist countries using it."

And the comeback: "Imperial is a vestige of colonialism."

[MJuric]

It's just like the age-old imperial/metric argument. It gets no one anywhere and just ruffles feathers.

"There are only two kinds of countries; those that use metric and those that put a man on the moon."

"Metric is so much easier to use."

"Thousandths are smaller than millimeters so imperial is more accurate."

"Metric is better because the best countries use it."



And it ultimately ends in: "Metric leads to socialism. Just look at the socialist countries using it."

And the comeback: "Imperial is a vestige of colonialism."

Unlike 1st vs 3rd I think there are significant differences between Metric and Imperial/Standard etc. I mean really, how many meters in a kilometer? How many yards in a mile? How many cm in a meter? How many inches in a yard?...what WTF!?

It gets even worse when you start looking at things like, how many grams does a cubic centimeter of water weigh? How many ounces does a cubic inch of water weigh?

I learned by fractions down to 1/64ths because I used them for years in the shop. I learned my "Fractions" in the metric system in less than a second because I could divide by 10 .

I'll be super pleased the day that metric material is readily available in the US. That is the last vestige of the metric system in the US. Even the old time shop guys lost there excuses because now most of their tools are digital.

[HerrTick]

One of the bass-ackward things about 1st-angle is that they do sections in 3rd-angle.

[jcapriotti]

Metric is another thing we would be converting to and I have less issues with it. Personally I can't see that metric or imperial has that much of an advantage over the other. For the US, its just the expense of converting, retraining, new equipment purchases to support it, etc. (Big expense and deal but I get the need to standardize on something).

But 1st angle makes no logical sense to me except that Europe went with it because its was developed from the first quadrant of coordinate systems, and 1 comes before 3 so it must be right. 3rd angle makes more logical sense, the right view of the part to the right of the front and the top is above the front view.

I know the argument is rather pointless, just needed something other than SWYMp discussions to drag us all down.

[jcapriotti]

One of the bass-ackward things about 1st-angle is that they do sections in 3rd-angle.

Wasn't aware of that, should be fun.

[MJuric]

But 1st angle makes no logical sense to me except that Europe went with it because its was developed from the first quadrant of coordinate systems, and 1 comes before 3 so it must be right. 3rd angle makes more logical sense, the right view of the part to the right of the front and the top is above the front view.

I think metric makes tons more sense than imperial on pretty much every level. the only thing that screws it up in the US is material thicknesses. 10mm is...1mm. .1mm is .1mm. .1 mm is .1mm. In Imperial that is ~25/64,~5/128 and ~ 1/256

In reality if you use decimal all the time not nearly as big of an issue but anyone using imperial also tends to use fractions on simple stuff as do a number of other things like drills etc.

First vs third is little more than, Flip a block over and where it lands is first angle. Flip a block over and drag it to the opposite from where you started is third angle.

[MJuric]

One of the bass-ackward things about 1st-angle is that they do sections in 3rd-angle.

Sections are based the direction the section is looking at, which way the arrows are pointing. They really don't have an angle of projection. Although confusing you could do a section view in third angle and drag it to the other side of the part and technically, as long as the directions of the arrow didn't change it would still be a good section view in third angle....but it would look the same as if you rolled it over as you would in first angle.

[mattpeneguy]

3>1
Prove me wrong...

[zxys001]

Round 1, Fight!
image.png

3rd will always win,.. our direct line of sight to any object is the projection we observe naturally.
Personally, I think the wording, 1st and 3rd is backwards.
1st (person, looking directly at object) and 3rd (party looking from the other side),... imho.

[jayar]

Both are equally confusing if one cannot 'see' in 3D to begin with.
3rd angle is equal to someone walking around a part and observing an object from each side.
1st angle is equal to someone remaining fixed and flipping the part to see the other sides. (Why is the bottom side shown at the top of the drawing?)

Using the above logic - anything you can't pick up should be done in 3rd angle and anything you can lift should be done in 1st angle. Case closed.

[Ömür Tokman]

It's just like the age-old imperial/metric argument. It gets no one anywhere and just ruffles feathers.

"There are only two kinds of countries; those that use metric and those that put a man on the moon."

"Metric is so much easier to use."

"Thousandths are smaller than millimeters so imperial is more accurate."

"Metric is better because the best countries use it."



And it ultimately ends in: "Metric leads to socialism. Just look at the socialist countries using it."

And the comeback: "Imperial is a vestige of colonialism."

Let's meet in the middle.
Impetric or Metrial..

[mike miller]

Both are equally confusing if one cannot 'see' in 3D to begin with.
3rd angle is equal to someone walking around a part and observing an object from each side.
1st angle is equal to someone remaining fixed and flipping the part to see the other sides. (Why is the bottom side shown at the top of the drawing?)

Using the above logic - anything you can't pick up should be done in 3rd angle and anything you can lift should be done in 1st angle. Case closed.

That doesn't solve anything. How dare you judge my weight lifting capacity?!?!? I have non-binary strength; if I just decide I can lift it.....I can.

[SPerman]

Does that mean I have to draw an X wing in 3rd angle, but Yoda can draw it in 1st angle?

[MJuric]

Both are equally confusing if one cannot 'see' in 3D to begin with.

^^^^^^This. The argument that one is better than the other is typically by people that have trained themselves to do one and can't do the other. Both are equally as easy if one simply visualizes the part in 3D to begin with.

The above is not true for Metric vs Standard. Dividing by 10 will always be easier than dividing by 12, 3, 36 or so on.

[MJuric]

Does that mean I have to draw an X wing in 3rd angle, but Yoda can draw it in 1st angle?

image.png

Yoda all angles will be.

[JSculley]

^^^^^^This. The argument that one is better than the other is typically by people that have trained themselves to do one and can't do the other. Both are equally as easy if one simply visualizes the part in 3D to begin with.

The above is not true for Metric vs Standard. Dividing by 10 will always be easier than dividing by 12, 3, 36 or so on.

These folks would like to have a word with you.

[HerrTick]

My dad was educated in Germany and learned 1st angle there. He was glad to leave it behind, as 3rd angle was more intuitive.

[Frederick_Law]

We should look at these from a 5th angle.

[MJuric]

We should look at these from a 5th angle.

Maybe if we just looked at both of them from a different angle?

[mattpeneguy]

Let's meet in the middle.
Impetric or Metrial..

Interesting idea...A compromise...Something like mixed units?...I suggest meters and inches:
1m-8"
That way everything works for all people...Problem solved...

[mattpeneguy]

Interesting idea...A compromise...Something like mixed units?...I suggest meters and inches:
1m-8"
That way everything works for all people...Problem solved...

To take this a step further and apply it to the OP topic, we could compromise on that, too. How about all top and bottom views should be 1st angle and all side views could be 3rd angle?
Anyone have any other problems I can solve today?

[MJuric]

Interesting idea...A compromise...Something like mixed units?...I suggest meters and inches:
1m-8"
That way everything works for all people...Problem solved...

How is that a compromise...that's what imperial already does 1ft-8". The compromise would be to do away with inches, feet, yards, miles and express everything in a decimal of some new unit...minches maybe.

[Frederick_Law]

Compromise.
12+10 = 22
22 / 2 = 11
We use 1cm = 11mm, 1m = 121mm

Let's see how long it take to land on moon again.

[Ömür Tokman]

Compromise.
12+10 = 22
22 / 2 = 11
We use 1cm = 11mm, 1m = 121mm

Let's see how long it take to land on moon again.

I am someone who loves conspiracy theories.
And I still don't believe people go to the moon.
USA, which has bases all over the world, would definitely have a military base if it went to the moon. Launching a ballistic missile from the moon would be less costly and more successful.
This is Putin's dream, to install ballistic missiles on satellites.

[Frederick_Law]

I think Elon is working on that.
To fire missile from the moon, you need to put missile on the moon first.
Guess why Elon is working on landing rockets?
Really just to reuse them?

I should work for conspiracy websites.
Imagine all the stories I can create.

[Glenn Schroeder]

I am someone who loves conspiracy theories.
And I still don't believe people go to the moon.
USA, which has bases all over the world, would definitely have a military base if it went to the moon. Launching a ballistic missile from the moon would be less costly and more successful.
This is Putin's dream, to install ballistic missiles on satellites.

Are you sure about that? First you have to get the missiles up there, and get the materials to build the base up there, and get the base built.

[mike miller]

I am someone who loves conspiracy theories.
And I still don't believe people go to the moon.
USA, which has bases all over the world, would definitely have a military base if it went to the moon. Launching a ballistic missile from the moon would be less costly and more successful.
This is Putin's dream, to install ballistic missiles on satellites.

Hmmm....... if we can't even keep our nuclear secrets, how could we keep a less consequential conspiracy secret?

Not only that, but the Soviets would definitely have discovered it was a conspiracy, and believe me, they would have told the world. They would never have kept such useful evidence out of the public eye.....

EDIT: See, this discussion inevitably runs off the rails.

[matt]

I would readily give up the inch system in preference for metric. Going through engineering school in inch units is a nightmare beyond description. Doing HVAC calculations in stones and figuring out when ounces is a weight or volume measurement, or all the nonsense around cups, teaspoons, quarts and hogsheads... We also used metric, and that part of it was so much easier.

But I'll never give up 3rd angle projection for 1st. That's just silly.

[Ömür Tokman]

Hmmm....... if we can't even keep our nuclear secrets, how could we keep a less consequential conspiracy secret?

Not only that, but the Soviets would definitely have discovered it was a conspiracy, and believe me, they would have told the world. They would never have kept such useful evidence out of the public eye.....

If you don't believe it, ask @RickB . Rick's company won the moon base tender. I could not remember the name of the company right now.

[Ömür Tokman]

I must have confused the subject too much, I'm sorry. It doesn't matter which one makes sense to me, the steering wheel is on the right or on the left, the way you get used to it is the easy one. we are using the 1st angle in Turkey. Also, in the drawings we made for Germany, the 1st angle and metric system. 3rd angle and metric system in our drawings for England. We use 3rd angle and inch in the drawings we made for America.

[HerrTick]

I think we can all agree... regardless of which system... always always ALWAYS have the "projection cone" symbol on your title block.

[jcapriotti]

You can get used to anything, hell I used and was proficient with Catia V4.

All things being equal, it comes down to what you learn or its just random and neither is better than the other. Am arguing that 1st and 3rd are not equal. 3rd is better because view location makes more sense, focused on the position to how you would look at the part. 1st angle was based on Monge's descriptive geometry and is based more on a mathematical/projection philosophy. 3rd angle was preferred in the US to train people on and was considered easier to teach and understand.

So 1st is based on projection and 3rd is based on viewing the part in person. Which makes more logical sense to our primitive tribal minds?

[jcapriotti]

I think we can all agree... regardless of which system... always always ALWAYS have the "projection cone" symbol on your title block.
image.pngimage.png

Thanks for the pic, I'll use it on my drawings going forward.

[CarrieIves]

The most important part is knowing which type of views you have. I find an iso view can help me notice that more quickly.

One of the most expensive mistakes in our company's history was because the engineers didn't realize that a component drawing was in 1st angle. It resulted in the pads for a ball grid array (BGA) chip being mirrored from where they were supposed to be. It wasn't something that could be "blue wired" as a rework. We have a heightened sense of awareness about that now.

[mattpeneguy]

The most important part is knowing which type of views you have. I find an iso view can help me notice that more quickly.

One of the most expensive mistakes in our company's history was because the engineers didn't realize that a component drawing was in 1st angle. It resulted in the pads for a ball grid array (BGA) chip being mirrored from where they were supposed to be. It wasn't something that could be "blue wired" as a rework. We have a heightened sense of awareness about that now.

So, in other words, never use 1st angle projection...ever...it could cost your company a lot of money...

[mattpeneguy]

Thanks for the pic, I'll use it on my drawings going forward.

image.png (84.68 KiB) Viewed 6225 times

Why isn't this in the default SW title block already?

[MJuric]

Hmmm....... if we can't even keep our nuclear secrets, how could we keep a less consequential conspiracy secret?

EDIT: See, this discussion inevitably runs off the rails.

This has always been my argument against all these massive, convoluted, conspiracy theories. We found out what President Clinton did with a Cigar and presumably there were only two people there when it happened.

You really think we could keep anything secret that involved 1000's of people. Furthermore you're expecting me to believe that somehow we have some people that are in power that can't seem to manage to balance a check book while other people in power can figure out some of these very complex precise operations?

Maybe it's my complete and utter loss of faith in the human species...there just aren't that many smart people left on the planet that can keep their mouths shut to be able to pull any of these things off.

[Glenn Schroeder]

This has always been my argument against all these massive, convoluted, conspiracy theories. We found out what President Clinton did with a Cigar and presumably there were only two people there when it happened.

You really think we could keep anything secret that involved 1000's of people. Furthermore you're expecting me to believe that somehow we have some people that are in power that can't seem to manage to balance a check book while other people in power can figure out some of these very complex precise operations?

Maybe it's my complete and utter loss of faith in the human species...there just aren't that many smart people left on the planet that can keep their mouths shut to be able to pull any of these things off.

. . . or as I heard someone say once "When you can show me three people that can keep a secret I'll start believing in conspiracy theories."

[MJuric]

. . . or as I heard someone say once "When you can show me three people that can keep a secret I'll start believing in conspiracy theories."

The only secrets are the secrets that keep themselves, George Bernard Shaw.

Most people can't keep a secret even if they are the only one that knows it. Two people, chance of remaining a secret is nearly non existent....really a secret that 100 people kept? Never happen.

[jcapriotti]

The purpose of conspiracies is so the elites can control the masses......wait.....does that qualify as a conspiracy theory? I'm so confused (because "they" want me to be, right?)

[MJuric]

The purpose of conspiracies is so the elites can control the masses......wait.....does that qualify as a conspiracy theory? I'm so confused (because "they" want me to be right?)

One of the funniest bumper stickers I've seen was simply "We are Everywhere". Just that. No affiliation to anything etc. I can only imagine all the conspiracy people reading it and saying "SEE I TOLD YOU!"

[SamSpade]

I agree that the third angle projection is more natural and intuitive, but then again that's all I've ever used... who knows.

As for the metric vs imperial, ideally metric makes more sense, being base 10. However, on the rare occasion time that I have had to use it, I simply detest it.

Over the years, we tend to develop a comfort or for a better word a feel for the imperial system. For example, for fits and tolerancing, I know what 0.001" or even 0.0005" is, I can almost feel it on my fingertips. Now, if someone were to tell me that there is a gap of 0.05mm in between two faces I have no feel what that is without doing the conversion. Maybe I'm just too lazy to embrace the metric system.

[MJuric]

Over the years, we tend to develop a comfort or for a better word a feel for the imperial system. For example, for fits and tolerancing, I know what 0.001" or even 0.0005" is, I can almost feel it on my fingertips. Now, if someone were to tell me that there is a gap of 0.05mm in between two faces I have no feel what that is without doing the conversion. Maybe I'm just too lazy to embrace the metric system.

unfortunately I think this is like language. From what I understand even people that are relatively fluent in another language "Think" in their native language and translate to the language they are speaking. I suppose at some point that goes away but when you've spent 25-30+ years dealing with imperial things it would probably take that long to become "Fluent" in Metric.

When I see "1mm" I have an idea of how big it is, but when I really start thinking about how big it is I often end up converting in my head to inches. This is even more true of anything not so standard..."That's 60mm"..."So around 2 3/8 inches"

[SamSpade]

unfortunately I think this is like language. From what I understand even people that are relatively fluent in another language "Think" in their native language and translate to the language they are speaking. I suppose at some point that goes away but when you've spent 25-30+ years dealing with imperial things it would probably take that long to become "Fluent" in Metric.

When I see "1mm" I have an idea of how big it is, but when I really start thinking about how big it is I often end up converting in my head to inches. This is even more true of anything not so standard..."That's 60mm"..."So around 2 3/8 inches"

The disparity between the two systems gets compounded when dealing with architectural drawings. ex.: 15000mm from center to center of columns. Too many digits before the decimal for my likely. I know, I sound like a grumpy old man.

[SPerman]

Imperial is better!

Common imperial force units:
lbf

Common metric force units:
kgf
Newtons

Common imperial temperature units:
Farenheit

Common metric temperature units:
Celsius
Centigrade
Kelvin

[MJuric]

The disparity between the two systems gets compounded when dealing with architectural drawings. ex.: 15000mm from center to center of columns. Too many digits before the decimal for my likely. I know, I sound like a grumpy old man.

...or 15M instead of 15000mm. Isn't this a bit like saying "I don't like imperial because there are two many digits to list 63360 inches in a mile"? The earth is 84145445920 1/64th's of an inch in circumference