When i merging two When open studio models the when i import the second models the first model is deleted?

edit

@Ziad are you trying to merge models in the OpenStudio Application, the SketchUp plug-in, or the floorspace.js geometry editor? I'm guessing floorspace.js, since that's the only tool that has a "Preview and Merge" feature.

From the user guide:

Your OpenStudio Model is not altered until you press the Merge button. Performing a merge translates your floorplan to a new OpenStudio Model that is merged them with your current OpenStudio Model file (OSM file). Any geometry in your current OSM file will be replaced by new geometry from the floorplan OpenStudio Model. However, non-geometry objects such as HVAC in your current OSM file will be preserved.

In summary,

• You're always working with one OSM file (there is no "first" vs. "second" file because the latest geometry is not saved as a separate OSM file)
• The latest geometry that you create in floorspace.js will be the latest geometry of your OpenStudio model