I am current working on an interface from a CAD system to CAESAR II. In our CAD system Z is usually up, and we currently transfer data with the Z-Axis Up flag set, so that the model is in the same coordinate system in both programs.

We have had a request to use Y-Axis up in the CAESAR II side, and rotate the cooordinate values as appropriate.

I would be very interested to know whether nearly all stress engineers prefer to use Y-up, or whether we should support both options in the interface. It is perfectly feasible to support both, but it does add to the complexity of the documentation and testing...

What do you think?

Casear has a flag to set Z up.
It is no suprise to me that Caesar uses y up as the norm.
God forbid that stress engineers should do anything that would be considered normal or straightforward!

Most of the people who use Caesar use Y up as that is the 'Norm' for The Caesar enviroment.
As an ex piper, the rest of the sane world uses z up.

So i suppose it depends on who the customer is.
I suspect the Stress engineers sat on the engineering pedastal would demand y up from the pipers.

Good luck

Gentlemen,

Long before the world of CAD was even around I was punching cards for programs such as Mare Island and Dynaflex these programs used +Y as up!

How and why CAD programmers chose +Z as up beats me but I am willing to bet they probably thought it was the way to go at the time.

ANSI for pumps uses a different axis set up, and others as well... I am sure each group had their reasons at the time.

Just be thankful that automobiles are quasi-standard devices... steering wheels and pedal controls, but some people drive on one side of the road and others the other side....

Which one is better or right? Both!

There must be a european directive for this.
(there is for everything else)

Hi Tim

Like you, we always (unless the client dictates otherwise) use Z axis vertical, for similar reasons - to use the same co-ordinate system as draughting.

Our pipelines are long cross country lines which we typically set out in true co-ordinates and so having the same axis system as draughting (ie Z vertical) is a must as it makes drawing checking and interface between draughting and design much easier.

In school, length and distance were X. When we started doing calculus, the second term was Y. With X & Y we could shoot a cannon, throw a ball or launch a rocket and fool around with distance, altitude, velocity and acceleration. X was range and Y was elevation. I never worked with Z for elevation in mathematics. I cannot remember a single engineering text where Z meant up.

But I'm not a designer. My guess is the designers' Z-up approach evolved from the 2-D plan drawings. The plan was primary and it was defined as X-Y. Then when elevations entered the picture, Z ended up.

That kinda' makes sense to me but the bottom line, as John Luf puts it, is - no big deal. No big deal to me, but then why did API 610 find reason to switch their coordinate system? I suspect some EN/ISO "standard" is the root.

Thanks to you all - it looks as if, like CAESAR II itself, we ought to support both coordinate systems.

It is not just the coordinates that will need flipping, it is probably restraint descriptions as well...

Metric Vs Imperial vs SI...

Or languages... we seem insistent on making life complex for ourselves.....

John C. Luf say:
"we seem insistent on making life complex for ourselves....."
I have the same feeling.But no more way to change it.
Regards.