Piping models vs. Isometric drawings

[zdas04]

[Rant]
I've always found isometric stick drawings (Iso) of piping fabrications to be confusing and difficult to work with. From the results I've gotten from people who say they like them, I'd say that I'm not the only one who finds them misleading. Especially when piping comes together at odd angles (few people can actually pick a 45[°] elbow out of an Iso).

Consequently, since I got AutoCAD 9 and CadWorxx I've been generating actual piping models to scale. The drawings are beautiful and have all the detail of a photograph of something that hasn't been built yet. Welders build what I've designed instead of what is in their heads. Pipe Fitters put it together right. It is so much more effective that I can't believe it.

Well, I guess I shouldn't believe it since I just got a call from one of my clients who required that I generate Iso's for a project that I gave him models on--he said that his field guys can't work from models and need the presentation they're used to. I asked him if he had actually shown the models to the field guys and he said "I don't have to, I know what they require". Meaning "I don't want to give them a better presentation than I've always given them because then they'll expect it all the time".

Like a good little whore, I generated Iso's for him. It is easy in CadWorxx to generate an Iso from a model, but the result is an Iso with material bullets so close together that I don't know how you tell anything from it.

I suppose the next call will require a blueprint.

[end rant]

David

 

[TGS4]

Amen

 

[Eltron]

The customer is always...uh...they're always...hrm...well, I'm pretty sure they are always something.

Dan

http://www.eltronresearch.com

Dan's Blog

 

[ewh]

It seems I am constantly telling myself that it pays the same when similar requests are made here.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[zdas04]

Dan,
The way I say that is "The customer is always the Customer". I used to say "The customer is always right--especially when he's wrong".

There's nothing to do about it. I got paid to build the models. I got paid to generate the Iso's. I'll get paid to go down there (South America) and tell a translator that what they built is not what I specified. It is just that sometimes you want to say "THE NEW WAY REALLY IS BETTER". Oh, I did say that (loudly) and to the guy's boss. I still generated the Iso's.

David

 

[MadMango]

The customer is always... writing your paycheck?

"Art without engineering is dreaming; Engineering without art is calculating."


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[patprimmer]

The customer is ONLY right when he pays his bills and does not damage your reputation to the point that he costs you more business than he gave you AND when you are not going to have to fix his stuff ups for free.

Salesman never get paid a bonus or commission for not accepting an order or walking away from a deal, but sometimes they should as sometimes it is the best result and should be encouraged where appropriate.

Even if you are a working engineer, when you deal with your clients you are also a salesman.

End of my rant.

Regards
Pat
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[waross]

You don't have to pass an IQ test to be a customer. When I was self employed I fired several customers.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[btrueblood]

Zdas,

You should've generated a rendered isometric view of your model, rather than a stick/line drawing. Or, put an iso view in the corner of the drawing. And reference the solid model file on the face of the print. This lets anybody who can read know that a model is available.

 

[zdas04]

What I gave them the first time was a rendered 3D model in isometric space. Not what they wanted. They wanted a stick drawing. I didn't think of sticking an insert of the model in the final Iso. My guess is that my client would have blacked it out prior to copying for the field.

David

 

[stanier]

Personally I prefer isometric drawings to models. I think models have introduced a complexity to design.

When we only had 2D drawings the managers and other non technical inded people kept well away as they couldnt read drawings. Now all can see a 3D model and all think they should say something. Move this ladder, more space behind that pump, why not put the pipe here.... The delays are interminable.

I have used models for 3 decades or more from the plastic built ones at 3/8" to the ft to the present day computer generated types. Both are difficult to take to the field.

Fabricators work from spool drawings and installers work from isometrics. To save costs some companies stopped producing spool drawings.

"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.

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[KENAT]

In my line of work models are over rated as a way of fully expressing design intent, but that's perhaps just my opinion, in my field, which isn't piping.

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[zdas04]

I've seen a lot of 3D models of mechanical things and mostly think that they aren't worth much more than the old way. On the other hand, a piping model is macro enough to make a really big difference in understanding. I did a design walk through with a bunch of field guys today and standing in the dirt, I was able to hold up a printout of my model and say "this is going right here" and people got it the first time. That has never happened to me before.

David

 

[stanier]

zdas04,

Pipe fabrication costs 3 times in the field as it does in the shop. The shop will use spool drawings not a model. What comes to the field will be pipe assemblies to minimise field welds. The model or print out may be of use to allow the trades to visualise the assembly. That is just how the brain works. I cannot myself see how a 3D model can contain all the data shown on an isometric. The data is normally contained in layers in a model. So now the trades have to be skilled in using a laptop based CAD package?

Or you have managed to generate 3D prints with all the isometric data thereon. This may be fine of all the data is embedded in the model as attributes.

"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.

http://waterhammer.hopout.com.au/

 

[zdas04]

Really, gosh I wish I had known how this worked before I spent 30 years doing it.

David

 

[stanier]

ZDS04,

Can you please post a copy of the model output you took to the field? Was it a hard copy at AO size? What data did it have shown? My most recent experiences is A3 size drawings being toted around. If your aim is to show the whole assembly I can see the point of the 3D output.

"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.

http://waterhammer.hopout.com.au/

 

[zdas04]

I'm not conversant with the "A" paper sizes beyond knowing that A4 is a bit bigger than 8.5X11. The drawings were 11X17.

The attached is not a Superconducting Supercolider, it is a pig launcher. It shows how two lines will come together to feed the launcher and still be able to add a future source. There isn't much to it, but I've had great difficulty over the years getting everyone on the same page using 3 plane drawings and Iso's. If I may speak hearasy, P&ID's have been zero help as well. With drawings like the attached, everyone was very comfortable that they knew what I wanted and I expect it to be built that way even if I'm not there. We'll see when the project kicks off.

David

 

[ewh]

I cannot myself see how a 3D model can contain all the data shown on an isometric.

Do you really mean that? An isometric is just a picture.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[patprimmer]

A3 is twice the size of A4 and A2 is twice the size of A3.

Regards
Pat
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[KENAT]

What am I missing?

That drawing Zdas just appears to be a shaded isometric.

Maybe terminology is different enough in the piping world from my aerospace/defense/machine design world that I'm just missing your meaning.

Following on from Pat, for practical use in this context A3 corresponds to B/Tabloid/11*17.

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