Revit doesn't calculate the real free area in a room?

[p.vicini]

Hi peoples,
i don't speak english very well so be patience !!

I saw that:
when you put a room tag with area in a room, it dysplays a right number ;
if you put a wall in this room, creating only a partial division, the number doesn't change!!
But the free area was surely changed loosing the plan surface of the wall just build
Is me that don't know how it works or it's impossible to have a realy room's free area automatically??
Ciao from Italy,
Paolo Vicini
Architect

[alpfra]

You must overlap the wall with Room Separation lines. (in italian Delimitazione del locale)

Ciao

[Mr Spot]

Walls automatically are room bounding and when you place a free instance of a wall in an existing room the area should adjust. It may be to do with your rounding increment of the area as to why it doesn't display any different.

Unless you have specifically asked the wall to be non room bounding then its footprint area should be updated...

[Taylor A]

P.Vicini......I think you are right. Tried drawing 2 rooms exactly the same. In one room I put several walls that didn't cross the room. The area tag reported the same for both rooms.

I would post an image but I'm having trouble uploading????

[Mr Spot]

P.Vicini......I think you are right. Tried drawing 2 rooms exactly the same. In one room I put several walls that didn't cross the room. The area tag reported the same for both rooms.

I would post an image but I'm having trouble uploading????
I just tested and the area updated fine? Try selecting the room tag or hovering over it, the boundary should highlight if it's not boxing around the walls then check to see if they're room bounding in their properties.

[Taylor A]

Mr Spot....I'll reply when we can upload images again.
"A picture is worth a thousand words"

[Taylor A]

oops....change of mind....the walls inside the room do get subtracted.

[funkman]

try this test....

draw a square room 10m x 10m: area = 100sq.m
place the room with area tag
then draw, say 3 or more, of the same walls inside chained, any which way

notice the figures decrease.

but then....
delete one by one the internal walls.
then look at the area figure???- not 100sq.m no more?

what gives with that? weird.

and then....delete the tag (and room) then re-insert a new tag. It shows 100sq.m again.

[beegee]

Took the test, but can't replicate the problem.

( Still can't attach views yet . :sad: )

[Mr Spot]

Okay i managed to replicate the issue. If you join any of the walls with the outer walls the area doesn't appear to change.

ie: area of the foot print of these walls isn't adjusted... Yet if you unjoin the wall from the exterior it subtracts the relavent area...

Definitely appears to be a bug at this end...

As i can't upload images at the moment. Check the revit city forum for my image of the problem...

[beegee]

Hmmm, ... Still behaves correctly here.

I join an interior wall to an external wall and the area updates, i pull the wall away and the area updates again to what it was originally.

I'm using the M_Room tag.

[Mr Spot]

I'm using CGA_Room Tag with Area, but i doesn't appear to make a difference which tag i use. Just tried the same tag as yours and still has strange behaviour...

[alpfra]

I send a example of the prob.
If you delte the internal wall the area value remain the same, but if you select the tag before deleting the red contour appear correct.

Regards

OPS i can't upload, interface give me some errors.
But i someone try the problem above, is very easy to understand, or try to draw a rectangle with walls, put a tag with area, and draw a wall which terminate inside the room:
the area value remain the same, my solution is to contour the wall with room separation lines.

Someone have problems to upload files???? i can't!

[Damo]

This was raised by a colleague at a recent UK Revit users meeting.

Columns don't affect the room area calculations, whether they are free standing or part of the bounding wall.

Just draw a simple rectangular room, not too large. Then, after you place a Room Tag, start whacking in some large columns. Note that the room area remains the same.

Now visit http://www.excuselist.com/ and see what excuse amply explains to your client why his financial calculations based on your overestimated commercial space figures are incorrect.

OOps! :Oops:

[Mr Spot]

Okay here's the examples of the various incorrect situations...

[lev.lipkin]

Bug had been left in the code from the time Revit computed rooms to the centerline of the walls. Wall which has its both sides in same room could be disregarded without actual reason while computing room area.

Next release of Revit would have this problem fixed.

I wonder if anyone would prefer current behavior (of disregarding area of the walls which stick inside the room without actually separating rooms)?

[aaronrumple]

Damn. I just finished a 90,000 floor plan where sq. ft. must meet clients requirements within a sq. ft. Guess I'll have to check it all manually.

This gets into an interesting discussion of product liability and BIM at this point.

[David Conant]

BOMA standards in the US allow for a 2% deviation between stated and actual area. This reflects the real world of construction where misplacing a wall by 1" (25mm) can easily lead to a difference in area of 1 sf (.09 m2) on a 12' (4m) wall.

Although an error this large seems egregious on paper, it is all too common in the messy world of a construction site. There is the perhaps apocryphal story of the site foreman who, when asked what accuracy he needed on drawings, picked up a sledge hammer and whacked the base of a wall. "That much"

[aaronrumple]

We had classrooms designed at 899.63 sq. ft. The client complained they were not "to program" at 900 sq. ft. Redesign ensued (at our cost). Multiple wing walls in the area could face affected the spaces by more than 2% (something I'm checking right now.)

The military also requires "exact" sq. ft. for housing. Not a sq. ft. more or less - substantially less than the 2% of BOMA.

Missouri has a new guideline on errors and omissions. Anything over 0.1% of the budget is considered fault of the architect and charged as such. We have to be 99.9% accurate. The bar keeps getting raised.

[bclarch]

Missouri has a new guideline on errors and omissions. Anything over 0.1% of the budget is considered fault of the architect and charged as such.
Wow. Where was the AIA lobbying group when this happened? Were they asleep at the switch or did they just get outmuscled?

[aaronrumple]

Outmuscled...

[David Conant]

I did a project for an intitution where offices were supposed to be 150 sf. Since this was a campus gothic style building many of the rooms had odd corners etc. We labled them with their true areas which ranged from 148 to 152 sf. naturally, a firestorm erupted. Stampeding egos were prepared to go to the mat over the unfairness of giving someone an extra 2 sf even if it was unusable space tucked into a niche behind a protruding column. After some revision, they received a new set of plans showing all rooms at 150.0 sf. Many compliments were issued about the skilful plan work. The only change: all labels were revised to say 150.0sf. In the finished building, variations in workmanship etc. would have resulted in variations far larger than the "corrections" we made.

[aaronrumple]

Yes, the old days we could have done just that. However clients these days are becoming more and more CADD savvy. They have AutoCAD and are looking in detail at information like this. They also have a 3rd party which is doing cost estimates. Even though it may be cheaper to a a few inches to the building - the space requirements are "legislated" by governing agencies that just might be penny wise and pound foolish.

Unfortunately, that is the environment we are all working in more and more. Almost all of our contracts have us re-designing the building for no additional fee if we are over the estimate by 5%. If Revit is off by 2%, then there goes almost half of my contingency.

[p.vicini]

Aaron....the problem is not the % of deviation !!! the deviation is considered on building something...after the project's measures.
The problem is that it doesn't work well!!
we can't be sure about the measures that we write on the projects not on the building deviation..that will come later..during the testing!!
I saw also problems in the calculation of the perimeter and in some other things...all chained at this problem.
I'm very slow to send my messages....many peoples answered ...and i must translate all ..lolol
I realy hope i made a mistake, if not we will have many schedules absolutely unusefull.
We will see,
Regards,
Paolo Vicini

[Roger Evans]

For Client Purposes Are you required & Do you also calculate area / room dims between skirting boards?

Had a problem with this years ago when I was employed ~ the client withholding fee payment as a result

[p.vicini]

Dear friends it seems we have some problems about calculations !

As i said, i did some little verifications around the behavior of the surfaces calculations in the various schedules we can have in Revit.

To begin i studied 3 situations considering 3 schedule’s types ( i used the metric system, the imperial one is impossible for me  ):
Floor schedule (testing area and perimeter parameters)
Room schedules (testing area and perimeter parameters)
Wall schedule (testing lenght, widht, area and volume parameters)


Sit 1 – 5.00 * 5.00 Square Room without any inside wall ( see the Simple square room.jpg attached)

The results about the Floor and Room Schedules are correct.
Those on the Wall schedule are correct, if you see the total but....and this is very strange.... the measures of area and volume of the single walls are differently written!!!!!
Why is it strange??? Off course cause the walls are EQUAL !!!
How can you write in an official document that the calculation 0,2*5.20*3.00 gets one time the result of 3,12, one other 3.00 and another one time 3.24?????
I’m sure that , also out of Italy , can exists only one result for single calculation.....

Sit 2 – 5.00 * 5.00 Square Room with a Wall ( of one meter lenght) starting from a perimetral wall ( see the Square room with Perimetral Wall.jpg attached)

The results about the Floor Schedule are not correct ; they don’t change at all !!!!

The Room schedule is not correct too....but the perimeter try to calculate the new date; it’s incorrect for only 20 square centimeters. Not too bad !! :-) Practically it doesn't calculate the thickness of the inside wall.
The strangeness is that when you select the room tag the the underlined perimeter is is graphically correct !!

On the Wall Schedule we have the same results that before; dates are correct in the total but the measures of area and volume of the single walls are differently written!!!!! And they can’t be different.

The calculations about the internal wall, according to the written dimensions is, as you see , wrong !! ( Area 1.10 * 3.00 = 3.30 not 3.00 – Volume 1.10 * 0.20 * 3.00 = 0.66 not 0.60!!);
But if we consider the real surface to calculate, that is : 1.00*3.00 = 3.00 and 1.00*0.20*3.00 = 0.60, the total is correct !!

Also the room tag is wrong!!!!

Sit 2 – 5.00 * 5.00 Square Room with a Wall ( of 2,5 meters lenght) putted inside the room ( see the Square room with Internal Wall.jpg attached)

The results about the Floor Schedule are not correct ; they don’t change!!!! Or for better saying the perimeter of the external walls seems correct if we don’t considere the perimeter of the internal wall ( i don’t know if this date must be necessary or not; surely this wall belongs the room. )

The Room schedule is not correct too.... the area parameter calculates the new date, but didn’t get the target; the area is not 24,52, but 24,50 square meters. Still not bad !! :-)))

About the perimeter the thing is like that for the Floor Schedule

On the Wall schedule we have the same results that before; dates are correct in the total but the measures of area and volume of the single perimetral walls are differently written!!!!! And they can’t be different.

The dates of the internal wall are correct !!!! how surprise... :-)))

The room tag is wrong!!!!

To end , last but not least, try to insert a structural column inside a wall of 15.00 square meters area and 10.50 mc of volume;

i think you have noticed that , when you add a windows or a door in a wall, the surface and the volume change correctly ( see the Wall With Door and Window.jpg attached) ;

what difference exists between the concrete and windows and doors??
The volume and the area of the wall don’t change when you put a column inside ( see the Wall With Column.jpg attached)

I saw those problems came from R5.1, R 6.0 , R 6.1

What do you think about ??
Can someone repeat my tests with the imperial system ? i did them with the metric one.

Regards,
Paolo Vicini
Architect

[beegee]

Hi Paolo,



I’ve merged your post with the previous thread as this is basically the same discussion.


Situation 1

.Revit is reporting that the wall instance is 5.2 m in all cases, which is correct measured center to center. Revit is not using this measurement to calculate the wall volume however. Because the walls are joined, Revit is allowing for the overlap of adjacent walls when calculating the individual volumes.

This may look strange , if you give that schedule to a client or consultant. I would not give them a schedule in this format, just give them the volume and wall mark.


Situation 2.


Floor Schedule.

As noted by Lev earlier in this thread, this is a recognized bug and will be fixed in the next release.

Room Schedule.

I’m assuming the problem with the perimeter is part of the same bug problem.

Room Tag.

The room tag is reporting the same data as the floor schedule, which has the bug.



Situation 4.


Column.

As mentioned earlier in this thread, and also in the Help
Room Area = The net area calculated from the bounding walls. Columns are ignored and not subtracted from room area.


The results and anomalies should be the same whether using metric or imperial.

[p.vicini]

Hi Begee,
i'm happy to know that the problem of calculation will be fix in the next release...for the moment i'm using, and studying, Revit only for presentations to the clientele and as support view to the planning. So for me is not a problem.

About the walls count, i have only a question: i understand how Revit calculates the area (cause it happens also with the area count) and the volume , but why they don't write the real situation of the wall measures independently from the type of calculation that the program completes??
I think it would be possible, but i’m not an expert off course.
It would not be better to make to appear the datum of the length of the wall, or the opposit option, in a compatible way to the final results? Cause is the single wall’s total, that we have to show in the schedule that is on the sheet, near the scaled design, and, for that, comparable.
In this way it would not expose the planner to the risk of a casual control from someone and to the, following, image of scarce professional reliability that would derive of it.
As it has well motto Aaron, the clients are informed more and more and very careful;
it doesn't seem me a good idea to leave them the possibility to find so formally coarse error.
I know , in this case it is a formal matter, but does the form have its importance, in contrary case we would not have job, doesn't it seem you??


As it regards the structural columns, and I generally think all the structural elements in Revit, but i didn't test yet, I didn't intend to say that their volume is not taken away by the surface of the room .
I wanted to make to notice that the volume of the structures should be taken away by that of the wall in which they are inserted, just as happens for the doors and the windows; don't you believe that the quantity of the armed cements must be escape from the quantity of the masonries?
Two of the attachements to my message show really this situation:
in the case of insertion of doors and windows, the volume and the area of the wall they decrease;
in the case of the insertion of a structure they don't decrease.
Normally the volume of the structure is not a negligible datum if we consider it as quantity that goes to decrease the total of the masonries.

I think this forum would be very usefull improving my english too 

Ciao,

[gravelin]

Paolo

it seems the calculation with structural columns is depending the type of material you're using.
With concrete you can attach the column in the wall and the volume is recalculated.
Picture 1 : before, picture 2 after attachment

[p.vicini]

Salut Yves,
how can you set the material in the structural columns??
I tried but taking those in cement or those in metal or wood, I have not seen a material parameter.
I added a material project parameter but nothing changed.
May you write me the procedure to allow me to try what you said?? did you see if it's works also with the other structural components??
Ciao,

[gravelin]

Paolo,

You must choose in the library the cement (beton) type of column (poteau in French).
After that, is is not possible to change the material.
But with this type of structural column, you can attach to the wall
Look in the rvt : it's done.

[p.vicini]

Yves,
i tried also with revit6.1, but it doesn't works like your.
I send my file not working; maybe is me that do something stupid and wrong,
ciao :-)))

[gravelin]

Paolo

You're on the way

You just need to attach

look at pictures

[p.vicini]

Yves..merci,
i always thoght it would be automatic, i didn't search on the bar!!!
Now, obviously, it works: i'll study better :-)
Good night!!!