How to have a bounding box fitting meshes group following shapes

I am currently looking to create a backplane behind my meshes. The backplane would follow the shape of meshes at the extremity of group.

Below a example of what I try to do. Green line (border of a plane) could be more or less adjusted with the shapes (red) depending of constant for example.


Any idea how I could do that ?

Minkowski addition - Wikipedia

This is implemented in clipper2-js here A native Typescript/JavaScript port of Clipper2 (

There’s a codesandbox example of using the library. Perhaps try a quick code sandbox with your shapes and calling the Minkownski class class in the library

Hope this helps or try asking Chat GPT

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The red part need to be created and does not exist initially.

Let me decompose my goal on only 1 mesh (If can do it on 1 mesh I would be able to do it on all of my scene meshes then):

1: This is what I am currently able to create. 1 SVG extruded that generate the black shape.
Then on the botton of bouding box I create a plane with same dimension and small height.

2: This is what I am trying to achieve.
Same extruded SVG but the background outline the black shape. Complexity comes because balck SVG have holes.