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# How to merge multiple OS spaces into one

If you have multistory spaces, is there a simple way to merge spaces created from floor plans? For example, I have a two story space that spans the second and third floor of a building. When I create spaces from floor plans, I end up with the lower half of the space on the second floor and the upper half of the space on the third floor. What’s the easiest way to combine those spaces into a single two-story space?

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In the SketchUp plugin, I would delete the 'top half' of the space, and use the push-pull tool to stretch the roof of the remaining zone to the correct height.

Alternatively, you could specify a double-height space for that single zone when you create zones from floor plans (say 30') and all the single-height spaces could be created with a 15' height.

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@Alex Krickx's solutions are very good choices. If you spaces are more complex and you can use this video as a guide on splitting and merging geometry. The move selected surfaces to new space can automate the cut/paste aspect from the video. If you select a subset of surfaces in a space it works as a split, if you select multiple spaces it works as a merge. In the merge use-case it does leave the empty space types behind. They can be cleaned up in the SketchUp Outliner window.

There is one other aspect to @mleach's question that I want to discuss here, which is stacked spaces in the same zone. One of the basic reasons for having a space object is so that the user can combine multiple spaces into a single zone, this allows you to re-zone your model without altering geometry. When more than one space is contained in a zone the forward translation to EnergyPlus converts matched surfaces between those spaces to internal mas objects. The resulting thermal zone has a clean shell without any internal surfaces. That works fine for spaces on the same story that share walls. But if you combine two spaces on different stories that share a floor/ceiling we end up in an odd situation. Lets imagine two 10'x10' spaces stacked vertically. OpenStudio will report 200ft^2 but EnergyPlus will only show 100ft^2. Depending on the mix of space types and the type of internal loads in the space you may have unexpected internal loads as well in the resulting thermal zone.

We created an issue to document this and come up with a better plan to address stacked spaces within a single zone. There are two scenarios for a stacked space. You might have two separate rooms on different floors that you want to be part of the same zone. This could be a stair towers where you want the area for each floor to get the right LPD. Another example is modeling a multi-story space that doesn't have an intermediate floor, which is more like Matt's case. One option is using the matched surface construction to determine which direction the translator should take, with an "air wall" construction representing the case where there isn't an intermediate floor. In the end this wouldn't change how we forward translate geometry, but could be used to overwrite the thermal zone field for area. If this is something that is needed a lot someone could prototype this in a measure, that would find any spaces in common zones with matched floor/ceiling surfaces. While thermal zone area is not exposed in the GUI, we do already have it in the API, along with height and volume.

Just to throw out another option for the case when you are using the space from diagram tool and have a variety of heights. Someone could make a custom version of this tool that uses the color or ...

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