Draw a spline around a group of different shaped objects

I’m working on a Three.js app that customizes windows. Users can choose different windows, resize them, and create a group of windows in any order they want.
I need to add new functionality to the app to generate a mesh(border/frame) around the entire window/windows group. To generate this mesh(border/frame), I should create an outline/spline around the group of windows.

This image shows exactly what I need to do

I’m not looking to do this using a texture solution like what OutlinePass does, link to the sample: https://threejs.org/examples/webgl_postprocessing_outline.html

Looking forward to your answers.

Thank you.!

Well, this kind of outline effect can be easiest solved with post-processing.

Why is not possible for you to use something like that? I’m not aware of any ready-to-use solutions that you can use with JavaScript.

Hi, thank you for your reply.
The reason I don’t use post-processing is that I need to generate a 3D mesh around all windows.
It is not going to be a simple line.