How can I create a grid outline effect similar to the one seen in XCOM?
From what I can tell a line renderer could achieve this effect but i have no idea how I might get the outer most points on a collect of nodes
I think he just wants to “select” group of fields (squares) and draw outline around them, so he wants to collect edge (outer) points to draw line.
This sounds more like math problem than vfx problem, this forum should be better place to ask about that.
If I understand correctly, you want to outline, where a given unit is allowed to move.
That is a quite difficult thing to answer as it fully resolves around how that logic is setup in code.
You could either use flood fill or actual pathfinding to determine which grid cells are reachable and then you have further possibilities to actually draw the outline. You could determine the outline (or moreover a mask) by comparing the outermost cells with their neighbors. If they are also walkable, draw nothing; if they are not walkable, draw on that edge. Then it is about how you grab the data and interpret it. If you just care about the corner points, you could use the above mentioned comparison to filter out the points as well.
Personally, I would do it on a shader level, by generating the needed geometry at runtime.
But details on code, setup, algorithms and optimization of that would be (as Qriva suggested) something that you ask in a forum more fitting to the problem. Here are probably enough people that could help but the chance is higher that you get help on the logic part somehwere more fitting. (and then you can come back for the VFX/TechArt part.)
I eventually found somthing close to what I wanted here