Sorry, this is not really 3d printing related. But as we have some cool folks here OS wise. I hopped you could help or point me the correct way.

As I have mentioned before my brother and I own a tiny narrow boat we are doing up.

The engine room is a nightmare. 4ft high with no top access. We are disabled (visual and flexibility basically old can't bend and classed as blind but some vision. ) So we have difficulty measuring exact space in a room we have to crawl through. Well it's very like Star Trek Jeffries tubes but greasy. ;)

We need to plan and mount electronics in there to support our use. (I sought advice on printing to help with this a while back and got fantastic help)

I am now starting to think having a 3d model of the engine room would make working out the layout much easier. So here is where advice is needed.

We are skint (poor for the US) so spending 1000s ain't an option. And likely not worth it anyway.

I have heard of android apps that use photographs. And that level of accuracy is likely fine for our planning needs.

But I'm a Linux 100% user. Since the late 90s So need some way to do this that can be done on Linux and fed into FreeCAD and or Blender.

Does anyone know much about tools in this space. And what the process for doing this with photographs is?