Kerbal Space Program

Updated to attach screenshots of the problem. Will update further with a debug script I used to track down where the problem originated at as well as logs that contain the relevant information.

Debug from testing:
[LOG 17:40:23.891] On Collision Enter for part: cupola
[LOG 17:40:23.892] part.collider = collider_base (UnityEngine.MeshCollider)
[LOG 17:40:23.892] Collider Hit: Launch Pad (UnityEngine.MeshCollider)
[LOG 17:40:23.893] Contact 0 Colliders: collider_top (UnityEngine.MeshCollider) :: Launch Pad (UnityEngine.MeshCollider)
[LOG 17:40:23.893] Collision speed 16.02857
[LOG 17:40:23.894] part.checkCollision() returns: False

The last line there is the important one; manually passing the collision info to part.checkCollision returns false, and the collision will not be handled. If I manually pass that same collision data to part.handleCollision() it will properly trigger an explosion.

This issue only effects the following stock parts (the only parts I could find with more than 1 collider):

Cuppola; this is the only one with a low enough impact velocity that it actually matters in-play; all others have a high enough impact velocity that they will (almost) always 'punch-through' and have their part.collider trigger explosions
    Mk3 cockpit -- the top window area on the cockpit will not trigger explosions
    Mk2 Cargo Bays -- doors will not trigger explosions
    Mk3 Cargo Bays -- doors will not trigger explosions
    Service Modules -- doors will not trigger explosions

Additionally, this bug may not trigger on every attempt; there appears to be some complex interaction regarding the precise physics setup at the time of collision; many times the cuppolas 'base collider' will still impact the pad and trigger the explosion even though it obviously hit the 'top collider' (e.g. higher velocities = punch through, so the part.collider still collides; regardless any collider that is not the part.collider will refuse to trigger explosions).

Can we please return this to a sensible method where any collider will properly trigger explosions? Perhaps allow specific exclusions with a per-game-object tag?

shadowmage45 wrote:

tater wrote:

Is it possible to update the Platform losing above, as it affects Mac as well and likely Linux.

Will likely need to wait for the devs (and moderators) to return from their vacation before we'll see much action on this issue. I have tried, but I do not have the ability to update platforms or versions (and I'm not even sure how I was able to update the status; seems there are some inconsistencies in the bug-tracker UI).

Just has to be someone who is anle to edit it, not neccesarily the devs. And of course, someone has to read what was written. I'll add it for you.

Nothing has changed regarding this bug; is still present in 1.1.3 with the exact same reproduction steps.

In order to confirm, look at the source code for the Part class. Note that it has a single 'collider' field, and that only the collider referenced via this field will respond to collisions via exploding; any other colliders on the part will not trigger explosions.

This is more of a modding / mod interaction issue as very few stock parts have multiple colliders, but tons of mod-parts do.

Confirmed with this test, thanks!