What determines bounding box size?

[Dr. Whammy]

Title says it all...

I just built a station that is 309m x 309m x 249m, yet the symmetry planes extend out well over 1000 meters in 2 directions. Here, if you look carefully, you can see the red symmetry plane stretching far out to the left for no apparent reason; since there are no docked entities or loose blocks leading out that far.

This is very concerning since I purposely set out to build a station to avoid generating the lag associated with my usual planetary bases in multi-player.

Everything runs fine in single player but I'd hate to spawn this thing in; only for it to open up a black hole's worth of lag, simply for existing. Does anyone know why this is happening? More importantly, is there some way to reverse it?

 

[Mork2]

Just encase this might be the problem is any of the ships docked to the station have large dimensions? If I remember right, the docked ships should also expand the bounding box.

If that doesn't help, a saved blueprint of the station with docked ships might allow someone to find out what is happening if its a loose or hidden block.

 

[Dr. Whammy]

Just encase this might be the problem is any of the ships docked to the station have large dimensions? If I remember right, the docked ships should also expand the bounding box.

If that doesn't help, a saved blueprint of the station with docked ships might allow someone to find out what is happening if its a loose or hidden block.

All ships and turrets have been undocked, leaving only handfull of 3 meter wide elevators. Ending dimensions are 309m x 309m x 241m with no loose blocks. The box still extends out into the distance. Is there anyway to make the box smaller?

 

[Mork2]

The dimensions will only show for the entity that your in. All it takes is one docked door or something with a loose block. Otherwise best guess to find the issue would be to blueprint the station and in a new SP world spawn in it and see it has the same issue there.

Has the game be restarted since the issue cropped up. As in if SP have you restarted the game? If MP has the server admins restarted the server since then?

 

[Mork2]

Opps I think I just ran into something that might by why your having that issue. I accidentally did 100 blocks in the wrong direction extending the bounding box shown by the mirror planes. It didn't retract when I removed the excess.

 

[Dr. Whammy]

Opps I think I just ran into something that might by why your having that issue. I accidentally did 100 blocks in the wrong direction extending the bounding box shown by the mirror planes. It didn't retract when I removed the excess.

I've been playing around with this thing some more and I think you're right.
This is the original station configuration at 309m 309m x 241m. As far as I can tell, it started out normally.


At some point, I was visually experimenting with an extended flight deck and shipyard assembly; basically placing some blocks to represent where this new docking space will be when the station is expanded. Its width increased to about 650m looks something like this.


I took your advice and spawned a blueprint of the station one sector away. The symmetry plane area for the station copy was normal but thinking back, I'm pretty sure this station was extended before being saved.

My observations.
- The bounding box size seems to be determined by the dimensions of the entity at time of spawn.
- The box scales up as the entity increases in size but does not appear to shrink back down even if the entity shrinks.
- Box scaling that occurs before a blueprint is saved does not transfer to newly spawned copies of that entity.

What do you think?

 

[Mork2]

I can confirm the bounding box doesn't reduce after extending even after restarting the SP game. Also if the bounding box blocks out that area for spawning in stuff then I've been wondering why so many of the turrets I spawn in don't show up might have to do with the bounding box and/or being to close to it. Normally it would just appear further off but now sometimes things don't spawn in at all.

 

[Dr. Whammy]

Do you think it might have something to do with being near the edge of a sector?

 

[Mork2]

Well I was going to say it didn't until I saw this. I'm very certain I never built anything on this out that far out. The ship for comparision purposes is a bit over 500m long....

 

[Dr. Whammy]

Wow...

Did you try spawning in a fresh copy to see if the issue persists?

 

[Mork2]

Tested a fresh spawn in a different world and yet the boundary reduced to normal.

 

[Dr. Whammy]

Did you dock your ship to a large station? If so, maybe the ship inherited the box dimensions from the combined mass of the ship and station.

 

[Mork2]

I have been constructing it so no other ships or it has docked with anything else.

 

[Dr. Whammy]

This is bad. If our observations are any indication, then every single home base in multi-player is a potential lag generator. Dock a ship to a station; the box gets bigger. Dock something to that ship; the box gets even bigger. Build a long rod/beam to dock a capital then lag goes through the stratosphere and the server CPU becomes a 286... Since collision checks are constantly running and because the bounding box never shrinks, the base amount of lag generated by home bases (with nothing docked) can (theoretically) only go up and never down.

I'm starting to think that you and I might have just discovered a bug; one that could be making multi-player exponentially worse for the foreseeable future.

I hope Schine see this and chimes in. Maybe they know a fix that we don't.

 

[Spartan4845]

This should be fixable, not sure if easy. Maybe have the entity recheck its size when something docks and unlocks? But that may cause too much lag

 

[Jojomo]

Are you thinking of a "bounding box" as an actual existing entity (not a SM "entity") or just as a concept?

You should only think of it as a concept.

Anyway, symmetry planes don't ever stop at the furthermost point of SM entities, and so aren't an indication of the volume that gets checked for collisions.

 

[Mork2]

True but anything you spawn will spawn outside the bounding box. I just recently found the stuff I spawned in that I couldn't find it was 2-3 sectors away in the direction stuff is suppose to spawn in..... I have to now clean out a small fleet of stuff that didn't appear at that time.

 

[nightrune]

F1 + F10 turns on debug mode and shows bounding boxes, beware it can create some client lag itself.