Calculating Overall Volumes

[james.austin]

Hi,

I've tried searching on this, but haven't had any luck so far - please feel free to redirect me if I missed a previous post...

We're working on several jobs now that require us to meet the Passive House Planning Programme (PHPP) standards. Basically, we need to input lots of data about the building into a schedule and it spits out a pass/fail result (much simplified, but thats the gist).

The main bits of data it needs are as follows:
1. Total external envelope volume.
2. Total internal volume of the building (to airseal line.)

We're using RAC 2011, and my bosses think it should be able to do that.

We reckon we can crack (1) above by using the STL exporter to generate a "shrink-wrap" of the building that we can then import as a mass and measure the volume.

However (2) is causing us some head-scratching, as I can't think of a work-around and my searching here has run dry. Basically If I could turn volumes on for an area, that would solve it?

Anyone come accross this? I know passive house design is growing in use and I've seen some US examples, so wondered if anyone had figured out a work-around? It would be great if anyone can help. I promise if we can crack it I'll write a blog and post the tutorial to share with the world!

Thanks in advance...

[arqt49]

Just a guess...
Fot the exterior volume you can use masses.
For the interior volume, rooms.
Both come with volumes.

[james.austin]

Thanks for responding......but:

1. A mass is not linked to the external envelope (unless it was originally used to create it, I think?), so it would not update automatically (hence potentially introducing user error), plus it would not accurately account for window indents etc.

2. Using rooms to calculate the inside area would miss out all of the walls and floor volumes (I also think?)

In my head, I figure Revit is parametric, so would be able to work this stuff out automatically. Perhaps I'm being a little too hopeful??

[Alfredo Medina]

Thanks for responding......but:

1. A mass is not linked to the external envelope (unless it was originally used to create it, I think?), so it would not update automatically (hence potentially introducing user error), plus it would not accurately account for window indents etc.

2. Using rooms to calculate the inside area would miss out all of the walls and floor volumes (I also think?)

In my head, I figure Revit is parametric, so would be able to work this stuff out automatically. Perhaps I'm being a little too hopeful??

I think you need to handle two different types of entities: a mass of the building, and the actual model; extract data from both, and then make some operations. It won't be automatic.

1. I think a mass is indeed linked to its envelope, through a parameter called "Gross surface area". If the mass changes, this parameter updates in the mass schedule.

2. Yes, that will give you the volumes of rooms. If you want a volume that includes walls and floors, could you start with the "Gross volume" parameter of the mass and then subtract the volume of the enclosure elements (walls, roof) of the model?