Rounding Up

[thredge]

Is there some formula syntax to use to get a formula result to display the rounded up number? We are playing with doing Occupant Loads from Area...err, areas, and of course setting the rounding doesn't always add that extra person when it is supposed to. Rounding a fraction of a person down is not agreeable with the code official.

Thanks.

[Dimitri Harvalias]

Had the same problem some time ago.
Check out this thread.
http://forums.augi.com/showthread.php?t=63566&highlight=rounding

[thredge]

*sputter, explicative*

OK, well I hadn't gotten to the rounding and adding error issue due to the rounding yet, so it looks like this is all going to be for naught anyway.

But for those of you that don't want to go read through the entire thread, the 'rounding up' workaround was to just add 0.49 inside the formula. So 1.01 ends up equaling 1.50, which of course gets rounded up to 2 and 1.00 ends up equaling 1.49 which ends up getting rounded down to 1.

Seems pretty ingenious (and I'm not saying it isn't) until I find out that because of Revit's 'totaling of rounded numbers issue' adding that .49 to all my areas causes additional problems in my sums, because it gets to add .49 to all the individual spaces then round the total.

My Schedule is attached and I compounded the issue by turning of Itemize every instance, so under OR -> Accesory Areas, 774 SF / 300 = 4 then in Post-Op 1 the math gets off really fast (1+12=14) Not much I can do about that I guess without a way to get the # of people rounded to an integer before revit does it's math.

Man I understand why Revit does it the way it does, or how at least, because it keeps the rounding error to a minimum, but why? One more frustrating Revit thing that we can't use just because it didn't quite get to where it needed to be.

[Dimitri Harvalias]

You have to keep in mind that you aren't actually adding the .49 to all of your areas, you are adding that the value that you want Revit to use in the calculation. Revit will always report the area for what it is. How you use it and how you choose to display it are up to you.
Using your occupant load calc as an example, if you need an occupant load based on the individual areas then the above method is fine. If you need an occupant load based on the total area then you would apply the rounding value to the total.

Don't give up on it quite yet. It may seem 'not quite where it needs to be' but sometimes it just takes a little adjustment in thought process. :beer:

[thredge]

Well, I got the rounding up in the individual spaces as you can see, but I didn't know there was a way to apply the rounding up seperatly to the total. I mean it is just a check box to provide the totals, not a formula I can edit. So I either round all the values and the end value or I round nothing...

We discussed it in the office and we would like to use the occupant load calculations, but the sums that look like they are in error really are a problem with submitting this report to any official.

Thanks for the help though, was talking to our Autodesk rep/support person and basically he said sometimes you aren't doing anything wrong you are just bumping up against Revit's capabilities. Seems like another case for that.

[dbaldacchino]

To just round up your occupant calculations and total them correctly, you need to do the following:

Create a calculated parameter to do your calculation (Area/occupany load factor) and then add 0.49 to it. Let's assume it's called CALC_OCC.
Create another calculated parameter and set it to be an Integer. Let's call this CALC_OCCint and set the formula to =CALC_OCC
Use CALC_OCCint as your real occupancy number, which now since it shows integer values, will total correctly with no rounding errors.

[thredge]

Yes, I didn't notice the last post of patricks that linked to the solution for that.

I did use that, but didn't actually create 2 parameters, the schedule let me create the calculated value and make it an integer value so I didn't have to make 2 separate calculated value parameters. So this fixes the main totaling calculation problem, making this pretty close to useable, so we will probably present it with a disclaimer in documents. Is there a different way some of you are doing the occupant load parameter? Mine is just a calculated value in the table itself, vs. a parameter of the room or area.

As you can see from the schedule I posted earlier, I caused another problem when I turned off 'Itemize every instance' the way I would usually calculate the occupant load would be to add all the areas of one type of use together then divide by the use factor to get the occupants...in this case it calculates the occupants first and then add them together, which gets me things like under O.R. -> Accessory Areas, where 774 SF / 300 equals 4 instead of 3 like it should. Which gets worse the more individual spaces I have in an exiting department, but I don't see a workaround for doing the math second. The nice thing is it is always a higher number so more restrictive, so I can put a discliamer on it explaining it, but still slightly frustrating. I just don't want to list 'Accessory Area' 4 times in each department in the schedule, just muddies things up.

[dbaldacchino]

You're absolutely right, no need to break it down like I posted. As to calculating occupant load, aren't you supposed to do it space by space? Otherwise you could run into rounding errors. At least for Net calculations....for Gross, such as Business, you're better off using Area plans. You can implement a similar schedule to calculate your occupancy for those areas. Then to document, overlay a plan view showing the Net areas (delete tags for Gross area) and an Area plan showing the Gross areas on one sheet view. Then you can also add a schedule for just Net areas and another for just Gross areas. Finally, add the two totals manually if you want your total building occupant loud (the last part is not very BIMish...oh well).

[thredge]

I got part way there, I went to an Area plan instead of the room plan to really see how far in error the room plan could be, and the results were interesting. I started another discussion on it with my results.

http://forums.augi.com/showthread.php?t=86269

Also, I'm pretty sure the way both the IBC 2003 and the NFPA 101 outline it is to take the whole area of departments without sub areas and just use that number in lieu of the rooms. You can see what an issue using the room areas to the inside of the wall can cause in that other thread though.