Question regarding default co-ordinate system orientation in SW

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.

 

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.

 

- 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?

- Ah, the old 'model for change' approach! Music to my ears ...

Rick.

 

<Sheesh>
See the drafting standards and the right-hand rule.
Pretty confusing if you never knew ...
Let jb use the other ... he'd never know.

 

Start with the plan view .... usually the X-Y plane
*on the drawing* (model can be anywhere in 3D space).
http://en.wikipedia.org/wiki/Plan_view
Other views "unfold" from the plan view which often
is the one than can show the most major detail in one view
(and often/usually takes the most space of any single view
on the drawing).

 

ANSI/ASME Y14.3

 

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

 

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.

 

<GAK>

Did you ever think that you are wrong & they are all correct?
Don't "reposition" them.
Correct your views. Check YOUR defaults. Or use another
import option.

 

The default view IS the X-Y plane in all CAD/CAM systems I
know ... and Z per the right-hand rule.
How you assign views to drawings is another option.

 

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

 

Mr. Mason,

And your point was? Need a custom translator or clean-up program?

You use left-handed coordinate systems down-under? No X-Y
cartesian defaults?

A thing to remember <g>.

 

Mr Huprich, it may surprise you to know that there are participants in

Rick,

Your comments suggest that you think Cliffy has used SolidWorks.
Here's a clue, Rick. Cliffy has never used SolidWorks. Cliffy has been
forcibly retired for years. He's a has been who never was.

Suggest you use Google to find any kind of specific response from
Cliffy in regards to SolidWorks that proves he has actually used the
program.

 

Rick,
Suggest you give clueless reading comprehension lessons <G>.
He's lost yet again (and probably has no idea what the
posts were about, as usual, due to missing buzzwords).

 

View *names* are probably "properties"/"attributes"/ .....

 

Posting crib notes again Jon?

The actual quote would be "Cliff, you are not even a has been, you are
a never was."

 

"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