# Grid Graph Edges

I’ve searched for quite a while now and hope i haven’t missed something totally basic: We’re currently developing a game that includes platforms in different heights. Sadly we can’t find an option to properly distance a graph from a platformEdge like when staying next to a wall.

Actual Behaviour:

Expected Behaviour (faked with erosion)

is there an option to also stay away from edges not only walls?

Thanks to all replies in advance!

Hi

If erosion works for you, is that not the setting you are looking for?

will erosion work the same as the collision check? eg. if my unit is 5 grids wide does this translate to a erosion of 3 (5/2 = 2.5; floored to 3 edit ceiled of course) and will block the same nodes around a wall as the collision check would do?

Yes. One iteration of erosion will expand the unwalkable region around obstacles and ledges by 1 node.

So i tried this and it seems like there is a difference that can get quite significant:
this one is with collision testing with a unit of a diameter of 2.5:

This one is with an erosion of 2 (2.5/2 = 1.25 → ceil to 2)

Yes, it’s not quite the same, especially when colliders are not aligned to the grid. However, it scales the same. So a diameter of 10 means the same thing as 10 erosion iterations.

The physics check uses a collision check from the center of the node. The erosion erodes away the graph on a node-by-node basis.

alright so erosion seems our best bet, should not be huge problem if we just scale everything to a unit using a integer amount of cells but thanks for the clarification, the fast answers and your great project!