My Brain Hurts (Auto Iso generation and updating)
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From: Paul Bowers <pbo...@pipingdesign.com>
To: Piping...@yahoogroups.com
Sent: Sun, 6 March, 2011 2:07:00 AM
Subject: Re: [PipingDesign] My Brain Hurts (Auto Iso generation and updating)
Excellent, outstanding! Thank you, Bani.
Paul
On 11-03-05 3:23 PM, BANI MITRA wrote:
>
> All Isometric generator programs must not be used as "out of the box", it will need lot of customization to match the standards followed in a particular project. It can vary from job to job and needs to be addressed at an early stage of the project. One widely popular Isometric generation program I am familiar with, has literally hundreds of "Switches" which can be set to get the desired effects, but it also requires reading of hundreds of pages of User's Manual and trial runs.
>
> But even then, all isometric drawings, after automatic generation, requires polishing by hand. In my experience, depending on customization provided by "Switches", each generated isometric drawing sheet may take another 1/2 to 4 hours of manual 2-D editing efforts to meet the project standards. We have developed a check list, customized for every
project, which all draftspersons have to follow to edit the generated isometric drawings.
>
> And it starts from a hard copy print of the isometric, as marked up in red by the piping lead or senior draftsperson!
>
> From my practical experience, I am facing another major problem - keeping isometric drawings current, as design progresses. We have a piping 3D model with database (electronic specification) to start with, and we have generated an automatic isometric drawing set with bill of material and the drawing is spread over multiple sheets. The bill of materials (BOM) will show all components with an individual tag number. These isometric drawings will be manually edited and released. Three months later, the layout is changed and there may be new hardware elements like two 90º elbows are now replaced by two 45º elbows, some more loops with additional lengths of piping and elbows are added, and so on. The changes can be easily
and quickly made in the 3D piping model, no problem.
>
> Problem starts thereafter. It will take a few minutes to extract another automatic isometric drawing set with multiple pages. But depending on the extent of changes, the number of sheets may exceed from original 3 sheets to now 4 sheets, and all tag numbers of BOM items will change. The revised tag numbers will affect both the drawing and the BOM table.
>
> Depending on situations, we follow different practices. If the changes are small, we re-run isometric generation, but only use the new BOM data to manually update the existing BOM table and also edit the drawing as needed. For elaborate changes, we have to void the earlier revision and manually edit the newer drawing set, as generated by the program, at the cost of additional manhours.
>
> I will like to exchange ideas with fellow engineers in this forum how they are managing routine updates in 3D piping
models and generation of isometric drawings, to keep pace with the progress with the project.
>
> Regards,
>
> Bani K. Mitra
> 2011-03-05
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