Question regarding default co-ordinate system orientation in SW

Not trying to start a brawl with this question, just trying to understand why the default co-ordinate system orientation in SW seems to be 'at odds'
with the rest of the world. I frequently exchange data with SW users and find that their models are always rotated such that the X-Y plane is vertical and the Z-axis horizontal. 'Real World' convention places the X-Y plane horizontal (ie you're standing on it) and Z-Axis vertical - or in machining parlance the X-Y plane is the table with long-travel in X-direction & spindle (vertical) axis is Z.
I suspect the answer is simply that someone chose an 'arbitrary' orientation for the default co-ordinate system in SW on Day 1, and it has been stuck there ever since. Can anyone offer a more-definitive answer?
TIA
Rick Mason MASCO Design Services Pty Ltd Sydney, Australia - home of the world-famous APEC Circus
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I don't understand where you obtain your sense of vertical and horizontal. Sounds like you are coming from the civil sector. For the civil sector there is an up and down and they refer to elevation and plan views.
In SW the global XY direction is associated with the first default plane that is, by default, labeled Front in the feature tree. It is also associated with the Front View. Since you can label the first default plane anything you want it is not clear what the issue is. Also, since you can redefine the Front view to be anything you want it is not clear what the issue is with SW. In other words, up and down is determined by the user.
As to what is best practice I follow the procedure I taught in Engineering Computer Graphics. The front view should:
a) Contain the least number of hidden lines
or
b) be the customary orientation of the part/assembly with the least hidden lines.
So I will choose the first default plane (labeled front by default) for the orientation that contains the fewest hidden lines. This allows me to automatically create a drawing that is 80% done most of the time.
Or if there is a customary orientation then I use that for the front view.
If I am working on the part that somebody else thoughtlessly created in some other orientation then I use the redefine view option to get my front view in the drawing.
TOP
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No, purely mechanical (although not in the wind-up sense). The question relates to the default orientation of the co-ordinate system for which there are several conventions - however, the one which I have always found to be universally accepted in engineering modeling is the one which I described with X-Y plane parallel to ground.

- OK, I'm understanding better how the initial selection is made. If X-Y Plane = 'Front' orientation as selected, then this is indeed at odds with engineering modeling convention as I interpret it, where the X-Y plane is associated with the TOP view.

- thus you are taking a drawing-based approach to the orientation of the part rather than an 'As Used' or Assembly / In-Car approach.

It is just possible that the person who created the model in some other orientation did so thoughtFULLY, following valid model-based rules!
Thanks for the input,
Rick.
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I've been around for twenty years in aerospace, automotive and a few others. I have yet to see a worldwide convention for the horizontal plane. It will typically be a convention in a particular company or industry. In structural engineering x is along the beam axis and y is vertical. So horizontal is in the xz plane. If you can cite and ANSI, ISO, JIS or GOST standard for this I'll take it under advisement. In days gone by the choice of coordinates was extremely important because modelers required placing geometry based on a global coordinate system. Pro/E changed all that and SW made the change popular.
I have found it is not uncommon for people to think the way they learned something is the way everybody does it. Asking such a question of SW is really a stretch because the choice of coordinates is totally up to the user. It is like you are asking yourself why you do this. Once you set up your default part template this should never come up.
A more appropriate question and one SW might answer is why use a right handed coordinate system instead of left handed? That is something you as the user cannot change and I seem to remember at least one aerospace application for a left handed coordinate system though I can't remember what it was.
The one thing I would say about choice of coordinates is that in many ways I consider a robust part to be one in which I can change the sketch plane for the base feature without losing the entire model.
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- Newbie, huh? <bg>

- Agree with your reasoning, but there is still a fundamental need for an 'agreed' convention especially in collaborative projects with in- puts from multiple sources (something we deal with frequently).

- So, if you model a simple solid and export it as, say, a Parasolid file how do you know what csys orientation is saved in the model - looking at it from the (external) perspective of shared data rather just drawing?
<snip>

- Ah, the old 'model for change' approach! Music to my ears ...
Rick.
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Rick,
I guess what I am still scratching my head about is why the concern? After all, within the SW community the global coordinate system is of little consequence. It is only when you start exporting to older CAD systems, CAM, 3D printing and other physical devices or when receiving input from the real world that coordinate systems matter. Given that it is possible to even define your own in SW this doesn't seem to be a big issue other than making it clear which coordinate system is being used when necessary.
Some concrete examples of where the default coordinate system can cause a problem are in order.
TOP
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We use 'another product' and frequently exchange solids data with companies designing with SW. In every case, their models come to us lying on their side, which means extra work to reposition them. This is not a concrete example, but frequently steel, aluminium, PET etc.
As you have helped me understand, the problem arises from SW ass- igning the XY plane to the primary Drawing view rather than distinguishing between a global coordinate system and Drawing views. Thus it appears that if you 'drop' an exported SW model, it falls sideways ...
Clearer now??
Rick.
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Mr Huprich, it may surprise you to know that there are participants in this Forum who are professional, knowledgeable and vastly experienced in sharing electronic data for 'significant' projects in various parts of the world - regardless of what software they currently use to achieve that purpose.
Your comments suggest that you may not number amongst that group.
R.H. (Rick) Mason Director, MASCO Design Services Pty Ltd Sydney, Australia
"It is better to keep one's mouth shut and be thought a fool than to open it and resolve all doubt." ~Abraham Lincoln
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On Wed, 12 Sep 2007 06:59:47 -0700, jon_banquer
Posting crib notes again Jon?
The actual quote would be "Cliff, you are not even a has been, you are a never was."
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On Wed, 12 Sep 2007 06:59:47 -0700, jon_banquer

"For the record I like SolidWorks" Jon Banquer April 10, 1998
"Without a doubt SaladWorks is a complete piece of shit" - Jon Banquer - May 21, 2006
"I've been away from SolidWorks for almost ten years." - Jon Banquer- Aug 2007
"The program has changed so much in ten years that I'm still way behind where I need to be." - Jon Banquer - Aug. 26, 2007
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TOP wrote:

This isn't even really true all the time since anyone can name their planes any thing they want. You could name them after the 3 stooges or the 3 bears or the 3 glockenschpiels. I think in early SW default templates they were Plane 1, Plane 2 and Plane 3. Mine are named XY, ZX and YZ, which makes no directional assumption at all.
Front Top and Right are arbitrary names established in your document templates. The individual user or company is responsible for the way they are used.
Daisy.
--
Posted via a free Usenet account from http://www.teranews.com


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Maybe you need to actually get out and DO some actual work for a change. Any damage done was probably because some SW poser sent a part to the machinist that couldn't be clamped properly because it _looked pretty_ in SW.
--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
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crossposting to 15 fictitious groups>

Go fuck yourself you lying bastard.
Just because they apparently aren't carried by your pathetic excuse of a news server doesn't mean they are "ficticious groups".
--



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pRecisionmAchiniSt wrote:

What use would I have for groups like: (quoting from your cross posted troll)
alt.penguin-fetish, alt.penguin-fetish.recovery, alt.penguins.bondage.latex.springs.bounce.bounce.bounce, alt.penis.erland-sommarskog.slapp, alt.battlestar-galactica, alt.usenet.kooks, alt.abduckted.by.lezbian-vampires.flonk.flonk.flonk
Sounds like groups frequented by retarded machinists, so you would know more about that than the rest of us.
Very nice collection. Now we know where you're going on that computer when you say you're working.
Daisy.
--
Posted via a free Usenet account from http://www.teranews.com


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Take a page from Ayn Rand. X=X Y=Y Z=Z
Front, right, top, etc. are conventions that vary by industry and discipline.
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Very true. As I design, I use the Front, Right, and Top planes to help me understand and orient the product. I make my decisions by 'What would an average user of the rpoduct say is the front, the top, or the right?' This is, generally (though there are exceptions) how I will model. It simplifies things - if it is an assembly, I don't have to worry about opening a part form the right view of the assembly and see its front when I get into the model -I don't hae to change my view of the total deal when working on just a part of it. This prevents, for instance, adding detail on the 'back' back of the part that will actually be on the 'front' of it when I get back to the assembly. it also makes it easier to understand for anyone I am showing it to or passing it on to for aditional design work
SWx is nice that the designer can design with the users mindset in mind, then the drafter can change the orientation of the part to pick the FRONT view that make the best drawing for the part, and the machinist can chosse the best orientation for machining the part. This makes a lot of sense.
After all, orientation is entirely arbitrary. I can put a product in your hand and you can hold it the way the user would hold it, or you can hold it in the direction of pull of the molded parts, or you can hold it in the way shown in the drawings. Let each professional in the process make the most informed choice of component orientation for their part of the process (for instace, anyone making SLA's will choose the thinnest section, usually, to be the Z direction to reduce build time. As Paul stated, this may not be the best for the drafter. It doesn't matter - its 3D, rotate the part!)
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- but it would seem that the X-Y plane orentation which then 'travels' with the model is thus assigned to what is, in fact a 'paper' orientation (ie the plane of the drawing-sheet) regardless of the original modeling intent. Surely the underside of the model in its preferred orientation for assembly should dictate the ground (X-Y) plane, rather than a Drawing view? Other considerations such as line-of-draw can easily be captured in the model as secondary references / PMI.

- I agree with the 'flexible' approach but not with 'arbitrary' or 'random' orientation. Our 'in house' rule is to model as assembled, as displayed in catalog/data-sheet or as common sense dictates if no other clues exist. Common sense, of course, is a very uncommon commodity!
At least now I understand WHY all the SW models we receive are turned with their primary profile skywards!!
Thanks to the (few) professionals who responded.
Rick.
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Have you looked into "Update Standard Views"? Look in the help under "View --> orientation". You can choose a new orientation for what is "Front", "Top", "Right", etc.
What it does not do is rename datum planes that might be named by orientation.
p.s. pardon me if this was already discussed. I did not see it amongst the noise.
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I'm querying this from an outsider's perspective (non-SW User) because SW models always import flipped on their side. I now understand WHY this is so (from the handful of 'sensible' replies) and it would appear that SW doesn't differentiate between Drawing-based orientation by named views and real-world 3D orientation by coordinate system. Both are needed in the 'grand scheme of things'.
Rick.
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Rick,
I would have to agree. SWCorp have just gone different to what i considered the norm as well. X-Y Plane being Top View. Given SW is very flexible in this aspect its just something i've lived with and it doesnt really bother me. Just a pity to see yet another standard none-standardized. :(
-HoffY
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