Material calculation

[clog boy]

For our day-to-day business we intend to use schedules for maintenance and calculation programs (odbc export). Question is: how reliable is it? Can we depend on Revit's accuracy for our business? Let's say a 97% accuracy means you're one unit short or in excess for each 30 units, which (for obvious reasons) is unacceptable.
Is there a way to achieve 99.9% accuracy? Please let me know what your experiences with schedules, shared parameters and odbc exports are.

Thanks in advance. Have a nice week and a wonderful X-mass.

[HawkeyNut]

Prettig Kerstfeest uit de Verenigde Staten, Bram!


Please let me know what your experiences with schedules, shared parameters and odbc exports are.

I have been using schedules for quite a while and have, on occasion, hand-calculated areas and take-offs just to check Revit's numbers. So far I have found that it is accurate. Even complex calculations like volumes under, and areas of, roofs seem accurate. I do not have any experience with ODBC... :?

[Scott D Davis]

My experience is that Revit is as accurate as the model that is created. When you start a Revit project, you start with a blank screen, other than what you may have added to a template. All the information is aded by the user, so Revit can only be as accurate as the information input by the user.

[clog boy]

I've done a material take-off for a composite wall (brick - insulation - air - brick) and it turns out that areas and lengths are calculated from the length of the center line. The way materials are calculated in this case is manipulated by the connection type, to my experience 'miter' produces more reliable results than 'butt' (which was true for the one specific project I bothered to check). When I do a manual calculation using Excel (using a method many contractors use) the difference between Revit's results and my results is (plus or minus) 0.2% to 8%.
Also, the length for interior walls that connect to the composite wall is calculated from the center line.

Eventually we'll try to do a php-query on an exported Access database, which adds data to a central library (which in turn is used by a well known maintenance program). But right now, it's a dream in the making.

[HawkeyNut]

I think it's important to understand that Revit is not meant to be a cost estimation tool. For that you should use more detailed third-party software. For simple volumes and areas it works quite well, well enough to help you through the initial design process and budget coordination. Once you get into things like wall assemblies, you should probably switch to the third-party software for more accurate numbers.

My company has started looking into Innovaya/Timberline for cost estimating...