Topic: Flattening drawings.

[Greg B]

I am just wondering how in the heck do you come up with the tolerances over that huge of an area.  Like big petro chem plants and stuff have so many parts and components.  Also how do you know when they build the plant that the workers are even paying attention to the model and or 2D drawing?  I have done some home construction in the past and had a footing off a good two feet or so.  We had to come up with a way of dealing with issues like that. 

I am being more curious than anyting.  Thanks

I can imagine they have tolerances.  His drawings allow for the manufacturing of the individual pieces need to be within tolerance so that they can be assembled in the field correctly.

[SDETERS]

But when the parts get assembled in the field the contractors and workers have tape measures or what ever to assembly and hang the parts by.  I am used to tolerances to +/- .0005 to say at the most +/-.100

I can not see how one can design for something that says has a tolerance of +/- 3 feet or more.   How and what position does that part take in the 3D model space? 

[TimSpangler]

A LOT more work because the files were LESS usable.

If the end result is the same how are the file LESS usable??

Our models are deadly accurate,

As accurate as the software they were created on. Then there is the translation to the the machine file (.iges .step, etc..) no loss there I'm sure

our machining is within tolerances which are noted in the spec.  Keep in mind that I did NOT say that 2D was useless.

Is that a 2D spec?? 
The point I am trying to make is this:  You can create a part with just a 3D model, heck its done on a daily basis
But without the 2D it cannot be accurately measured.  You have yet to address this point.

You can however create and measure a part very accurately with just 2D. That to me makes the 2D more usable to me. 
3D is great if you live in a perfect world.

We have that data, why don't you?

Absolutely, It's on the 2D print. Along with the datum structure for measuring the tolerances.

Not anymore, all nine levels of the structure now interfere with each other at elevation zero.

So for YOUR work this may not be a tool that you take advantage of,  but it doesn't discredit its use for someone else.

- Maybe I missed the sign on the way in
WELCOME TO RANDY'S WORLD
VISITORS WELCOME
*don't get comfortable your just visiting*   :ugly:

No I don't, never have.  It may in some cases for some users, in our case it would be disastrous.

Are you saying it now??

So to sum things up, Joe's tool (  ) would not work for YOU, but as we can see by some of the other posters, it will work great for them. as long as they don't send their files to you.

Your fingers, your keyboard, you don't HAVE to click on the topic.

I just stop by in between flattening drawings and exploding dims.    Plus its Friday, and ALL the supervisors are on VAC 

[Greg B]

I'm a little confused by everyone's animosity towards Randy.

Are you all in the exact same type of work that Randy does?  Does your business have the exact same business practices?  The exact same contracts?  Are they the same size as his?  Use CAD the exact same way?

[Greg B]

Are you saying it now??

So to sum things up, Joe's tool (  ) would work for YOU, but as we can see by some of the other posters, it will work great for them. as long as they don't send there files to you.

their

[CADaver]

I am just wondering how in the heck do you come up with the tolerances over that huge of an area.  Like big petro chem plants and stuff have so many parts and components.  Also how do you know when they build the plant that the workers are even paying attention to the model and or 2D drawing?  I have done some home construction in the past and had a footing off a good two feet or so.  We had to come up with a way of dealing with issues like that. 

I am being more curious than anyting.  Thanks

Everything is spec'd.  Most of it by the governing codes such as API, ASME, ACI, AWS, AISC and the like, the rest by us or our client.  We check facilities just like we check drawings, only we call them inspectors... dozens of them.  Here, your foundation above would be inspected by at least three inspectors.  Errors still happen, that's what jack-hammers come is sizes.

[Greg B]

Everything is spec'd.  Most of it by the governing codes such as API, ASME, ACI, AWS, AISC and the like, the rest by us or our client.  We check facilities just like we check drawings, only we call them inspectors... dozens of them.  Here, your foundation above would be inspected by at least three inspectors.  Errors still happen, that's what jack-hammers come is sizes.

why

[CADaver]

Just one question I may regret asking, but I'm well aware that 3D drawings are much more usable than 2D and accept the fact; heck I live it.

What if you're in the situation where you're doing simple site plans, and your CAD tech's don't know how to manipulate or use a 3D drawing. 

Doesn't happen here.  First we don't have but a couple "CAD Tech's" we use "designers" and engineers, and they are quite skilled at what we do.

Maybe it's just for a drainage analysis... whatever...

Drainage analysis requires much of the 3D data contained in the file to calculate flow rates volumes and velocities.

What's wrong with taking your model, flattening it, cleaning it up a bit, and pushin' out the drawing.

You mean, other than breaking the 3D data we've invested time and money placing in the file and making a much less usable file out of it?  Nothing I guess.

There are situations where people don't know how to use a 3D drawing, and that does not make them any less successful of a CAD tech or designer or engineer than anyone else.

It may not, but they won't work here very long without becoming proficient in 3D.

This LSP routine has as valid a place in someone's arsenal of tools as any routines in yours.

As does exploding dimensions.  We've seen folks post on this very forum, what they consider are very valid reasons for exploding dims.

[CADaver]

But when the parts get assembled in the field the contractors and workers have tape measures or what ever to assembly and hang the parts by.  I am used to tolerances to +/- .0005 to say at the most +/-.100

I can not see how one can design for something that says has a tolerance of +/- 3 feet or more.   How and what position does that part take in the 3D model space? 

I don't know of any construction field with a tolerance of three feet.  Even highway rock blasting work.

[Guest]

Are you saying it now??

So to sum things up, Joe's tool (  ) would work for YOU, but as we can see by some of the other posters, it will work great for them. as long as they don't send there files to you.

their

 

[SDETERS]

I don't know of any construction field with a tolerance of three feet.  Even highway rock blasting work.

What are your tolerances typically.  Just being curious I know this is going out of thread a little bit (sorry for this)

With the standards you mentioned how do you spec those out?  Or say this part to be inspected  or made per ASME 14.673niner (I made that spec up)  Is it on a word document?

[Keith™]

I'm a little confused by everyone's animosity towards Randy.

Are you all in the exact same type of work that Randy does?  Does your business have the exact same business practices?  The exact same contracts?  Are they the same size as his?  Use CAD the exact same way?

Absolutely not, in fact, I know that 3D modeling can produce a tremendous amount of information that CAN be useful, however, in many diciplines, the information, although it CAN be useful, is not.

From the architectural side, I can draw a model in 3D and generate sections, but they do not meet the minimum standards.

Ok, why you might ask ...
Several reasons, but I will address one big one ... in sections we are required to show connections, fasteners, insulation, air spaces, anchors, etc. Since these almost never occur at the same location in the drawing, we would be required to have dozens of sections. Further, we would also be required to draw all of said fasteners, insulation, etc. While that might be a neat thing to do, and would make a great BOM for a structure, while we spend hundreds of hours designing a 3D model that is "completely accurate" (if the fasteners were missing it wouldn't technically be accurate), while our competitor has designed 10 structures in 2D

Ok, so lets say that you have one of those fancy ADT thingamabobs ... Autodesk says "sorry, you don't need to show plates and studs in your wall designs", ok, fine ... no plates and studs means no stud anchors, straps and fasteners. We show a wall without fasteners and some jackass builds it without fasteners, we end up being sued by some slick lawyer who contends that they were just following the plans ... hey you showed everything else, we didn't know you EXPECTED us to put fasteners THERE ...

I have seen some of the worst who are supposedly knowledgable people, try and build something without the slightest knowledge of how it is supposed to work. In the end, no matter how much more usable a 3D model is over a 2D plan, it is only usable from the design aspect, not the construction aspect, or at least it is that way in my field of architecture.

Further, as I have stated earlier, there is not one piece of software available that allows me to create a correct elevation of my 3D models. If I draw a 3D model of a log home, just so I don't have to do elevations and sections, I will sadly disappointed when I have to draw them both, this time in 2D, just to get an accurate depiction.

[CADaver]

Most of our project are along the lines of some of those you've seen me post; major petro-chem projects, in the $200M-$1.8B range.  We have in the past also executed several other types of 3D projects from commercial building, highway, pulp/paper, power generation/transmission.

Interesting...

You say "We" as in your company.

What kind of projects have "You" worked on?

IN some capacity or another, I've worked in all of them.  My background is Civil/Structural so that is where most of my experience as a designer resides.  Though I've had a turn in Piping and Mechanical, I've also covered other tasks from Civil/Structural Design Lead to Project CAD Coordinator to Project Design Coordinator to Construction Manager.  Last year I was "moved" to "Corporate Manager of Design Applications" (glorified CAD manager with none of the fun).

[Greg B]

Are you saying it now??

So to sum things up, Joe's tool (  ) would work for YOU, but as we can see by some of the other posters, it will work great for them. as long as they don't send there files to you.

their

 

I thought you weren't going to be around here today.

[CADaver]

A LOT more work because the files were LESS usable.

If the end result is the same how are the file LESS usable??

Because to get those same results we didn't USE the files, we used pencils and calculators.

Our models are deadly accurate,

As accurate as the software they were created on. Then there is the translation to the the machine file (.iges .step, etc..) no loss there I'm sure

So far well within tolerances.

our machining is within tolerances which are noted in the spec.  Keep in mind that I did NOT say that 2D was useless.

Is that a 2D spec?? 
The point I am trying to make is this:  You can create a part with just a 3D model, heck its done on a daily basis
But without the 2D it cannot be accurately measured.  You have yet to address this point.

AGAIN I have never said 2D was useless, no matter how much you wish I had, I haven't.  I have said the 3D was MORE usable.  Is that a concept that escapes you here that one thing can be MORE usable than another without impacting the others usefulness at all??  Or must it be for you that if one thing is useful the other can NOT be??  Truly they are not exclusive concepts.

You can however create and measure a part very accurately with just 2D. That to me makes the 2D more usable to me. 

That makes it usable yes, 2D is usable, I have never claimed otherwise.  I can place the VERY SAME data in a 3D model, so at that point they are identically useful.  however I can glean even MORE data from the 3D file and therefore it is MORE useful.  You may never use the data, that does not mean the data is useless.  A screw driver is useful for turning screws even if you NEVER use it to do so.

3D is great if you live in a perfect world.

It's great even in mine.

We have that data, why don't you?

Absolutely, It's on the 2D print. Along with the datum structure for measuring the tolerances.

Then why do you keep asking for it??

Not anymore, all nine levels of the structure now interfere with each other at elevation zero.

So for YOUR work this may not be a tool that you take advantage of,  but it doesn't discredit its use for someone else.

My position remains that stepping on an accurate 3D model is a bad idea, I don't care who is using it.  Stepping on it reduces its usefulness, even if YOU never use the data for YOUR work, someone has used it or they would not have built it that way to start with.

No I don't, never have.  It may in some cases for some users, in our case it would be disastrous.

Are you saying it now??

Saying what now?  (your little "sign" slur butchered the quoteback)

So to sum things up, Joe's tool (  ) would work for YOU,

No it wouldn't, as I said above it would be disastrous.

but as we can see by some of the other posters, it will work great for them. as long as they don't send there files to you.

Use it, yeah they can use it.  I've seen guys use their teeth for bottle openers, doesn't follow that its a good idea.  Stepping on an accurate 3D model, breaks it and makes it less usable.  Stepping on an inaccurate model results in a flat inaccurate model.