Factorio Forums

In 0.17.30 the collision mask option "not-colliding-with-itself" has the behaviour of acting as a global whitelist of prototypes that don't collide with any other prototype with the flag. However the name implies that the prototype should only not collide with itself when it has this flag. Tested same behaviour in 16.51.
This has been questioned so raising for an official ruling

To test

1. Modify the file: data\base\prototypes\entity\demo-entities.lua
2. Set the collision mask for both the player.player and assembling-machine.assembling-machine-1 to:

   Code: Select all

   collision_mask = {"object-layer", "player-layer", "train-layer", "consider-tile-transitions", "not-colliding-with-itself"},

3. Load a new game and via editor place an Assembly Machine 1 and 2 on the map
4. return to play mode and your character can run through the Assembly Machine 1, but not the mk2 version.

i'm pretty sure it's for buildings that consist of multiple sub-entities.
Like this you can simply give your entities (that all are placed in the same collision box) that flag and you won't have issues with blueprint ghosts etc.
Giving this flag to a moving entity was surely not intended
of course only the sub-entities would get this flag (and only this flag), and the main object (that you build) doesn't get it, so you can't build two of these buildings on top of each other

for me, this is 100% how i'd expect this flag to behave.. or actually even better because i thought it was just a normal collision mask that only works for *one* sub-entity, and not for multiple

Set the collision mask for both the player.player and assembling-machine.assembling-machine-1 to:

If both entities have the same collision mask, then its working as intended.

thanks Klonan, you have clarified a point I had missed around the need of the entire collision mask list needing to be identical and not just having the same layer for the collision to not occur if both entities have this option flag.