Prologue (Truly Basics)

There are numerous software for 3D modelling out in the world today. For people in oil and gas industry, certainly to have come across several of them.

The basic software widely used by either operators, contractors, or consultants is non other than Autodesk famous software the AutoCAD.  This legendary software has been used for centuries.

But the early AutoCAD like so many early CAD software, built for manufacturing design in mind. It basic built, transferred to the next generation CAD software. This of cause, it’s a perfect solutions for design purpose.

In the event of the introductions of rapid coordinate acquisition of laser technology in the 90’s. the role of CAD software is also evolve. The Laser technology is use now to capture a 3D image of an object. Combined together with powerful computer processor in the last decade and rapid development of CAD software, the 3D as built modelling is born.

This however, presented a new problem. Some of the already widely used software like AutoCAD, Microstations, and PDMS, are not built originally for as built modelling.

In my early article, I already mentions the purpose of as built 3D modelling, which hold the key phrase: SPATIAL. This ‘SPATIAL’ is related to manufacturing, designing or to be more specific branch  in oil and gas industry: FEED (=Front End Engineering Design) process.

The software I mention above, used in early design of a complex/plant, accommodate  a very ideal environment. For example, if we design a pipe route, we will design it with ‘ideal situation’ like a’ ideal’ degree elbow which 30, 45, and 90 degree like. But in the reality, when the pipe route is built, for any reason, the elbow will not take the ‘ideal’ degree. It may be 32, 46, or 85 degree. As such the pipe run will not take the turn as the same as the design drawing.

The much later CAD software, built specifically for as laser built modelling are very adamant of this problem. And several as built CAD software can also export the 3D model it generate, to the design CAD software.

But this however, presented a new problem. Many EPC company have having trouble because this dualism CAD software. When they tried to clash the as built 3D model with their design 3D model, they must struggle to import the 3D as built model to their 3D design model. Especially when the 3D as built model is embedded with geodetic coordinate, the X,Y,Z in world datum like WGS.

As one coordinate of an object in 3D as built model can exceed E10 digits, the 3D model of design CAD software generally don’t have this capability, as 3D design model never tied to world coordinate. So when we force the as built 3D model to integrate with the design 3D model, the 3D as built model can not be accommodate by 3D design software.

Many EPC consultant or company usually trick it by a number of ways, most notably, the as built 3D model is stripped by it’s geodetic coordinate.

Here is a few sample of it:

These elbow showed here, modelled by Cyclone, a native software for as built modelling.

These elbow made by PDMS, a native software for design modelling. Notice the elbow angle on both program.