BIM-Technology-Range

Thursday, April 19, 2007

Draw, modify, coordinate, schedule

Whatever you will do modeling a building, especially build up a BIM, every elements should go through these 4 steps.

To draw is the easiest and toughest task. It's very easy to build anything in 3D you want. But to make it a reasonably easy object for the following 3 steps - modify, coordinate, schedule, is a kind of state-of-art.

To use the pre-packed libraries comes with the BIM softwares will help you through this. However, if that's a 3-dimensinoal hyperbolic skylight in your mind, then you must prepared to spare more time on this "draw" step. The best way is to go through all the 4 step as trial run to make sure your home-brew object is good enough.

But life is not like that. There are cases you have to change objects you made to an extent that you have to make a new one to replace it. Check the software and your drawing convention that you could do that revert/remake in a non-painstaking way.

As an example I give here the least possible trade of building elements in the world a designer would like to coordinate (or even to get a peek) - "builder's work" shown in a CBWD (combined builder's work drawing). Yes, a hole in a wall/slab for a pipe to go through! But they mean money to builder if they're not coordinated.

But I was told to schedule them out from a tower BIM into excel sheet!!



Like everybody I was scared with this idea. Instead of blaming the guy who ask the question so late (BIM was built and modified for almost a year), I turn my full attention to the software function to see if this could happen with minimal working hours.

Luckily I found that there's a feature of the software to put the results of a "measure" command into an object, like doors or windows. Eventually I can schedule out these "measure objects". What my draftmen have to do is:

- convert all "void" geometries (objects that making up the holes in walls) back to positive solids. It's a one step procedure for a whole floor. That means a 70 steps for a 70-storey high tower

- 2 "measure" commands for each discrete solid, so we could have the surface area and depth of each particular builder's work. It's painstaking but it's routine. 2 working days were spent for the first 15 floors. (including learning curve)



In the end, I spent half the time of traditional method (use calculator and CBWD hardcopy) to come up with the schedule, with the outcome could be reused for other revisions. Also, it's about 1/5 of time to reorganize the BIM to schedule out the works in normal way.

Conclusion : life is different from theory, but they all start with theory.

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