RE: Double-Dimensioning

We use MicroStation J (v7.1) with PlantSpace Schematics for doing the P&ID's, and MicroStation 95 (v5.5) with Omni-Pipe for 3D pipe routing. Once we've done the pipework in Omni we then export it back on to the network (Omni will only work on files stored locally on the machine) and extract the hidden line files using MicroStation J. The design of everything else (structural, electrical, etc.) is done using MicroStation J in 3D. I've only done 3D on MicroStation (starting back when it was V5) and found it really easy to get started as the 3D side of things seems to be well sorted with excellent viewing commands and a good selection of easy to use 3D tools.
A few years ago I had a try at doing 3D in AutoCAD (v12) and found it a nightmare, but it may well have improved since then so I can't comment.

Omni will work in conjunction with Isogen to produce Isometrics but there are some problems with the linkup to the catalogue that I've yet to address (these are mainly to do with Piping Specials and out-of-spec flanges), although these seem to be caused by a problem with Omni rather than Isogen (namely that the number of characters allowed in a component's part number isn't long enough!). Having said all that though, we do use it as it gets the iso's started but they still require some manual alterations before they're ready to be printed off.

I've had a look MicroStation's equivalent of Paperspace ("Drawing Composition") and can see some benefits but I'm not sure if it would be worth the effort. Also anybody we take on would have to learn something new as none of them so far have had experience of working with "Drawing Composition" (including me!).
At the moment we create a new design file with the same filename as the drawing and then reference in the border and all the components of the 3D model (the 3D model is broken up into several files for each discipline e.g. piping upper deck, piping lower deck, etc. as this gives us greater flexibility) we then generate a "hidden line file" from the model and reference that in to the drawing too, and then switch off the display of the 3D model. So we are left with a design file with the border & hidden line file visible and over these reference files we place the dimensions, notes, etc. everything needed to finish the drawing off. This is how we do all our drawings as these days I tend to do everything in 3D, in fact the only 2D drawings I've done for a while have been the schematics!

Nathan.

• Original Message from PipingDesign@egroups.com at 26/07/00 01:34
  >Good comments below. Of those on the list that are involved with CAD drawing
  >production to some extent (which is likely almost all of us), which software
  >are you using? Are you doing 3D modelling with automatically-generated iso's
  >and paperspace-style G.A.'s?
  >
  >It might be interesting to see what others are using to get the job done and
  >your thoughts on the pros and cons of different packages.
  >
  >Paul
  >
  >
  >> >Although I'm getting more and more engineers
  >> >demanding double dimensioning and also repeating information
  >> The refuge of lazy boneheads who won't read and remember technical
  >> references. And doubtless the excuse is that it's so easy to be redundant
  >> with CAD. Double dimensioning is like two pressure gauges on one tank.
  >> With one gauge, you always know the pressure--with two gauges you're
  >> never quite sure.
  >>
  >> >The danger is people are getting so wrapped up in CAD technology that
  >their
  >> >forgetting basic draughting principles. These principles have evolved
  >over
  >> >time and some are just as applicable to CAD as they are to manual
  >> >draughting.
  >> Too true. I see it in the FEA end of the biz--doing what seems cool
  >> rather than what needs doing. A lot of people imagine that running CAD
  >> software (or FEA for that matter) _is_ engineering has transformed the
  >> engineering process. Not true--the engineering process is exactly what
  >> it's always been--organizing and communicating instructions, based on
  >> physical and mathematical principles, so artisans may take materials
  >> found in nature and give them a specific usefulness. CAD or FEA is only a
  >> tool which at best enhances the product (in this case the graphics). At
  >> worst CAD simply tarts up schlock so as to provide the illusion of
  >> competence. For better or worse--the underlying process and principles of
  >> design don't change.
  >
  >
  >
  >
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