Objects to library

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Fugro BTW NZ
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Objects to library

Post by Fugro BTW NZ »

A job I have recently undertaken required QC/DC checks of approximately 80 flanges fitted to a large oil refinery component. The component was constructed of exotic alloys which meant that most, if not all, of the flanges were non-standard and so were not available in the Cyclone/Cloudworx library of components.

Our alternative strategy was to then extract the required flanges as meshes from the 3D design AutoCAD model supplied by the client and then import same into the parts library. This would have given us each of the flanges (possibly with a relevant UCS to the design vs. as-built) to then effect a best fit into the scan data.

This however proved to be not do-able and we had to fall back on a combination of growing cylinders and patches on each flange which enabled us to generate a relevant flange face centre. Also some flanges had insuffient scan coverage for this degree of modelling and had to be left unprocessed. Unfortunately this result was well short of what we had planned but thankfully we had an understanding client.

Does anybody have any advice on how this type of job could be more carried out with greater accuracy and hopefully less manual input?

Regards,
Tony Daamen
HDS Surveyor
Fugro BTW Ltd
New Zealand
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Phill
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Re: Objects to library

Post by Phill »

Tony

Sounds like you had an interesting time. I've been modelling shapes for a few years now and I have found the fastest way is not to rely on Cyclone fitting shapes to clouds but doing it yourself with a limit box and spinning the pipes/flanges to look down their axis and adjusting it by eye. This involves using the insert->cylinder tools and manipulating the object with the ctl alt and shift keys. I find most of the time this method will give a more accurate result than the fit to cloud functions, especially on steelwork.

I know that this can be difficult on a flange as they have a very short axis, but most of the time the flanges are aligned with the pipe behind them, which usually has a longer axis.

As to getting the objects from Autocad into a part library, it is hard to pass comment without actually having a look at the autocad data and examining what can be extracted. I understand that there may be confidentiality issues here but you can send me an extract of the data if you would like me to have a crack at it.

Hope this is of some assistance to you.

Cheers

Phill

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Re: Objects to library

Post by noorwiramaz »

Hi there, Hi every one,

You may visit this web...it might help for DC works,
http://www.accura-surveys.com/Best_Fit_Software.htm

Cheers....

Noor Wira,

Kuala Lumpur, Malaysia.
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Fugro BTW NZ
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Re: Objects to library

Post by Fugro BTW NZ »

Hi Phill,

Thanks for your reply. In the end we pretty much modelled each flange as you described, though we used a patch grown on the outer face of the flange to locate the 'Stand Off' dimenson of the flange by extending the (grown) cylinder to meet this. Problems arose on flanges that had reducer configurations on the incoming pipe and on those that were particularly one-sided or sparse in scan coverage which made it difficult or impossible to model with any accuracy (=time wasted). In a few cases we imported a flange mesh directly into the scan data and did a visual check.

Keep in mind that visibility was difficult in some areas during scanning due to scaffolding, personnel working and restricted choices of scanner set-up position. This was immediately prior to cladding being fitted while major internal work (ceramic tiling, NDT, etc) was still under way.

The attached screen dump will give you some idea of the project and shows the cylinders (red) and patches (light blue) used to set the scan to 'site/design' UCS and the individual flanges (dark blue) imported as meshes from the design model. The differences of placement of some of the flanges are due to 3D model errors rather than construction error. This vessel is the largest of 3 components scanned and was laid horizontal during construction/scanning.
Stripper screendump.JPG
Cheers,
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Tony Daamen
HDS Surveyor
Fugro BTW Ltd
New Zealand
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