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1st angle projection vs 3rd angle

    
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Mike

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Registered: 2002-8-28

Message 1 of 6

 1st angle projection vs 3rd angle
15-02-2010 08:48 . am   |   View his/her posts only
I would like to solicit some help from those familiar with the ISO, JIS and GB drafting standards. I know the default for the DIN drafting standard is 1st angle projection. In 14.30, all of our view commands reflect this.
I know the default for ANSI drafting standard is 3rd angle projection.
I guess I need to ask two questions.
1. What is the draughting standard for ISO, JIS and GB; 1st or 3rd ?
2. Should VX change its default view layout commands to match? Currently if you specify ISO standard you still get 3rd angle projection.
I don't want to request this change based on what I read on the internet.

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ChrisWard2k2

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Registered: 2011-11-22

Message 2 of 6

15-02-2010 09:10 . am   |   View his/her posts only
Hi Mike

Traditionally, projection is a choice, it does not have to be specifically married to a drafting standard. Large companies, such as aerospace manufactures etc, define their own in-house standards which typically are based on an international standard but with their own preferences and legacy requirements. VX already provides the flexibility to accommodate this, wouldn't a change be a downgrade?

It would be cool for VX to offer the choice of decimal point or comma to mark the decimal place.

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Mike

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Registered: 2002-8-28

Message 3 of 6

15-02-2010 10:32 . am   |   View his/her posts only
My fear in requesting the change was that it was going to feel like a downgrade. That is why I posed the question. The DIN standard has always been 1st angle and we set that correctly. However, it could still be changed by the customer. It is just my opinion but If you select ISO standard then we should tailor our commands to adhere to that by default, still allowing for customization.

In reference to the comma, I am surprised we don't offer or enforce that part of the draughting standard. How about the space?

6.6.8.3 Each group of three digits reading to the left or to the right of a decimal sign shall be separated by a space from preceding digits or following digits respectively, except for four-digit numbers designating years.
EXAMPLE 23 456 2 345 2,345 2,345 6 2,345 67 but the year 1997


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Paul

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Registered: 2011-9-17

Message 4 of 6

15-02-2010 03:26 . pm   |   View his/her posts only
Hi Mike,
the issue does not require familiarity with the standards.

If you choose a standard setting, the attributes should adhere to the standard otherwise the setting is misleading.

If you start customising then you are more likely to be departing from the standard. However this is the users choice and irrelevant to VX setting.


In MCAD, there is not much activity in the 100,000.05 plus dimension zone so the space/comma issue is largely irrelevant. Typically the increasing value eliminates the decimal point since we have tolerancing and units which enable clarity in numbers.

I understand the over riding requirement of draughting is clarity of communication.
IMO the ISO space separation is potentailly confusing in it's own right and probably computationally difficult.
I don't think anyone will complain that VX is not adhering to that part of the standard.
So there are some instances when adhering to the standard perfectly is not always perfect!


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Kevin

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Registered: 2004-4-26

Message 5 of 6

15-02-2010 03:30 . pm   |   View his/her posts only
Mike ISO, as used here in the UK can be either 1st or 3rd. I have customers that claim to work to ISO but use both projections. I think projection is something that (if I am being honest) a lot of people do not really understand. I say this because I have a supplier who rings me up constantly asking me to remove the projection symbols on my drawing templates and replace views with arrows on the plan or on an iso view. So this is what I now tend to do, draw an iso view with arrows marked View 1, View 2 etc. Belt and braces, as they say.

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ChrisWard2k2

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Registered: 2011-11-22

Message 6 of 6

15-02-2010 07:20 . pm   |   View his/her posts only
Hey Mudcrab

Quote

so the space/comma issue is largely irrelevant
It is, but I'm more concerned about the decimal point symbol. It is a specific requirement of the ISO and BS standards (8888) that a comma is used instead of a dot for the symbol. The comma is in fact normally used in Europe. In some countries, I don't know but VX may actually be using the comma because it is the system default, set within the regional language on Windows (Control Panel). However, here in the UK at least, the use of the comma as the symbol is generally restricted to drawing dimensions, we normally use the dot for things like spreadsheets, monetary values etc (you can rely on the Brits to be different!). The comma is chosen simply because it is easier to see and not so easily 'lost' by paper copiers. With the exception of at least the decimal point symbol, dimension standards are matched-up by VX, the trickier question is whether or not orthographic projection should be too.

In the case of ISO/BS, projection can't be set in stone, both 1st and 3rd are used, it depends on Company/Industry/Country as to which is favoured. However, the drawings I have seen from around the world tell me that even if the drawing standard does call for a specific projection, this requirement is not always adhered to. There are plenty of DIN standard drawings using 3rd Angle. Maybe they were not drawn in Germany, I can't remember - when you have joint multi-country projects like the Airbus A3xx series, a lot of standards cross-pollination occurs. In fact, since ISO has moved on, the related DIN may well have done so too, in which case it would formally support the use of both projection methods. Perhaps Snoopy can help to clarify?

The JIS and GB standards may be more terse, but they are also aligned with ISO, more so each year, possibly driven by the global market needs and likely the fact that European engineering standards are mostly well researched, well thought out and practical (thank you Germany and France!). It seems to me that we are not far from having a single world standard series for most engineering requirements and ISO is leading the way.

As it stands, VX could add support for the comma as a decimal point symbol, plus perhaps the UNI (Italian, based on ISO) and GOST (Russia and surrounding territories) dimension standards -that might be more useful than second-guessing view projection requirements.

By the way, via Config, you can have VX put in view projection arrows automatically (cool!), but they look like section view arrows, not what many would want unfortunately.
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