Filling a mesh with a colour

I have an idea of creating a tactical space in VR of territory control, and to leverage the 3D immersive component. The player would play the game by having a global 3D overview of the situation and getting inside the map to make changes.

As a start, the “3D unit” to be used would be a small cube, around an 40cm side. To make this, I’m hence trying to paint space with a transaprent colour.

Hence the question : how is it possible to fill a mesh with semi-transparent colour, to make so that the player can get in it, and see the world from there ?

I’m not sure I understand your goal but I’ll give it a shot.

If you want to have a semi-transparent material, you can use the Translucent blend mode: documentation link.If you still want to see your cube while inside, you would need to activate Two Sided. This is the easiest method I can think but you may encounter graphical glitch with the combination of Translucent and Two-Sided.