As @Sonder says, if you import the model into the file, work on it from there and then reload it, whatever you worked on will be replaced by the external file.
You included the sections inside the component after importing it and then reloaded it, replacing it with the external file, which had no sections.
In this case you should keep your sections in the section model root and you shouldn’t group them. Grouping sections will affect only what’s inside the group.
Besides the issues you got, there is a major issue that derives from inserting sections inside components and then reloading them: the relationships these sections have with scenes become lost when reloading. Their active states become all messed up.
@colin I’ve made extensive reports about this in the past, but they are still standing. This is a huge blow on collaborative workflows, like the ones we try to keep at our office. Please try to push some buttons there…
I don’t think this is something that can be “fixed”. Once you place anything inside a component or alter it in any way, you have edited that instance of the component. So reloading the component with the original component file does exactly that…replaces it. That is a workflow issue, not programming.
What you can do though, is create a group that contains the component and the section plane (outside of the component). This is a very useful technique that I use with my site model. It allows me to create a section plan view of the structure without cutting into the terrain. This way, you enter the group, right click on the component and reload. This doesn’t affect the section plane or scene since the section plane is not in the component. You need to do this as a first step prior to setting scenes…or, of course, have it preset in a template.
@PBulhon You should also pay attention to what Sonder said. You can pick your sections and your component and group them. This way you can move them around together and the sections inside the group won’t affect anything else in the model. As reloading a group isn’t possible you’ll never miss a reload and have to get inside the group to reload the component.
And watch out for how you save your ‘base’ reference model, per @colin . You have to remember to save the base model with NO active section plane before reloading it in the secondary model, which habitually trips me up. Whatever section plane you leave as active in the base/reference will come in with the reload as active too, regardless of ‘local’ scene settings or how you had the old version of the reference set up.