Sliver Space - What is this?

[d.stairmand]

In Project Information - then Energy Data - What on earth is "Silver Space"?
mine is set to 304.8

[jtobin.68416]

I'm not sure what Silver Space is, but 304.8 is pretty much exactly how many millimeters are in 12 inches.

John Tobin

[Mike Sealander]

I can only confirm it's a quantity used in energy modeling for the room object. Search this forum for Kyle Bernhardt and the answer will probably show up.

[mmates]

It is Sliver Space and not Silver Space. A Sliver Space is a small space like a gap between two walls. The sliver space is used with the analytical model and not the physical model when analyzing heating and cooling loads such as with Revit MEP. Imagine a new wall being constructed about a foot away from an existing wall for aesthetic reasons. This one foot gap is usually considered a sliver space.

[jeffh]

The sliver space tolerance is a setting at which small "sliver spaces" will be ignored when the analitical model is created for gbXML export. For example a chase wall the space between the walls is a sliver space.

This is important because when spaces are analyzed to create the analitical model the criteria used to determine if a wall is exterior or not; is if it has rooms on both sides of the wall. If it does not, the wall is considered "exterior". So in the case of the chase wall you could end up with the analitical model identifing the 2 walls of the chase as "exterior" when in fact they are not. This mis-interpetation of the model will create inaccuracies in the energy analysis of the model.

The sliver space tolerance allows you to have these small conditions where you would not normally place a room object and still get accurate results during energy analysis. So if you have these kinds of small spaces where you do not typically place rooms make sure your sliver space tolerance is large enough so they will be ignored. Otherwise you need to place spaces there for accurate energy analysis.

Besides just chase walls you want to look for other small rooms where you would not typically place a room object, such as closets or elevator shafts. These are often too large to be captured by the sliver space tollerance settings. These areas need to have rooms placed into them for better building analysis results.

[d.stairmand]

Cheers Jeff!
It was one of those "What on earth is that Button for" buttons.

You must have a Great Revit Technical Encyclopedia there!

[vugsus]

Thanks Jeff. This make it quite vivid.

[amey2003.146380]

So is it ok, if I will set this value as zero in case I am designing a new house????

[ckidd]

The sliver space tolerance is a setting at which small "sliver spaces" will be ignored when the analitical model is created for gbXML export. For example a chase wall the space between the walls is a sliver space.

This is important because when spaces are analyzed to create the analitical model the criteria used to determine if a wall is exterior or not; is if it has rooms on both sides of the wall. If it does not, the wall is considered "exterior". So in the case of the chase wall you could end up with the analitical model identifing the 2 walls of the chase as "exterior" when in fact they are not. This mis-interpetation of the model will create inaccuracies in the energy analysis of the model.

Jeff, I'm using RME 2011 for gbXML export, for import use in HAP. I had a sliver space in a chase (1'-1" in the short dimension), so I deleted the space before exporting. After exporting, the spaces that share those walls were analyzed correctly; they were not counted as 'exterior'. While this is what I was intending, it seems to counter your above quote in bold.

The time the export feature has saved me is incredible, but I'm trying to make my gbXML exports better, so less 'tweaking' is required after I'm in HAP. In the process, I'm trying to understand better what is going on under the hood.

Does your above quote apply to Revit Architecture and 'Rooms' (as opposed to RME's 'Spaces'), does it apply differently to Revit 2009 (maybe the export function has been improved in 2011), or am I missing something entirely?

I really like the results I'm getting right now, but I don't have a SME to point out when I'm headed in the wrong direction...