FCU+MFC Stability issues and difficulty (and tips)

[AcE Tech]

Though I'm very impressed with this mechanic when I started playing the game, I feel there are some area's that might need improvements.
I have spend around 150 - 200 hours on engine tuning on ships and would like to address some issue's I'm running up against a lot of times.
Maybe someone can shed some light on it, or maybe it can be used by the devs to improve this mechanic.

The following issues I have been fighting a lot while having not found a clear solution yet :

#1 Ships are not stable (stay aligned) over the full (forward) thrust range.
I noticed a lot of ship seems to fly straight at first glance, but might not actually fly straight if you give it only a certain amount of thrust (like 20% to 24% forward thrust).
This is of course really annoying, but also really confusing. I don't directly see thrusters hitting the max thrust limit yet so the controllers should just be able to correct with more thrust. What is even more confusing is that in some cases the ship has alignment issue's in BOTH directions (like up and down pitch) at different speeds.
Example : A ship might start nosing UP when @ 20% to 24% thrust, and would start nosing DOWN @ 45% to 55%. While it does fly straight in all other thrust ranges and it even does fly straight when attaching heavy objects on the outside of the ship (though it might change/shift the alignment issue effected thurst range).
I have been battling this problem a lot, and have yet to find a solution and I kinda suspect it is just a problem/bug/limit of the FCU+MFC.

#2 Getting stable ships to hard? (Correction/stable area is to small?)
As this is a game and not reality, I kinda feel the stable area ( the amount of correction the FCU+MFC can to so the ship starts snapping into a straight line) is to small.
I have met a lot of people who are running against alignment issues on their ships and abandon there projects because they can't figure out how to fix it. A lot of them actually seem pretty symmetrical and should be flying straight at first glance. The problems range from wide area's: incorrect naming, not connected or bolted engines/hardpoints to beams. But a big part of the ships I helped with also seem to just not like the engine numbers that are pointing in different directions. Sometimes adding more engines in a sideway's direction would make the ships stable, while the single engine that was already pointing in that direction was far from 10.000K thrust.
Example #1 : An Engines pointing sideway's, would not keep the ship straight while outputting only ~2000 thrust. Adding 5 more engines in that same direction and putting them all in the same group makes the ship seem stable, but eache engine is only firing ~450 thrust. So multiply by 6 engines in that direction, is only ~2700thrust (700 more). Why could the single thruster in that direction not just fire an extra 700 making it also 2700 thrust total? It can thrust even all the way up to 10000 if needed, but the MFC seems to limit it, but then unlimit it a bit with more engines?
The same can happen the other way around, where to many engines in a direction also seems to make the ship unstable:
Example #2 : A ship has a line of 9 sideways thrusters in one group on the sides of his ship that doesn't fly straight, reducing the number to 6 suddenly makes the ship stable.
If I run against a ship with this last problem (example #2) I'm alway's getting very unsure about this total ships stability. As often changing only one engines on the ship can suddenly make it go out of alignment again. It also often experiences the #1 problem where the ship is not stable of the full range of forward % thrust. I also have the idea that this problem often happens when a ship had angled engines (either angled backward or angled side thrusters)
There are a lot more example of strange things happening, but in general I kinda wanna say that it seems to hard for a lot of players to get a ship that just reliably keeps flying straight. In my eye's the correction factor / stable area should be a bit bigger so that it is a bit more forgiving to ship builders about the mass center and engine placement/tuning/naming.

#3 Accelerating and Decelerating bumps alignment
Every time you accelerate or decelerate (between 0 and 100 thrust) almost all ships do a little bump/tilt making the ship not follow the original direction you pointed the ship at. I have no idea how to solve this yet. However I have seen 1 ship that seemed to only get minimal tilts and I don't know why yet. It did have a tower of maneuverable thrusters far behind the main engine group, so it was a bit of a unique design that might have helped, but this is not achievable with majority or ship designs.
Example : Enter a ship, disable cruise mode, and start tapping the throttle, letting the ship switch between 100% and 0% thrust. The ship will randomly start tilting its pitch and yaw, sometimes pretty big, mostly small steps.

Thrust vs Mass center?
I guess some people might wanna say that you should build ships with aligned mass and thrust centers and to some degree I agree with this. But I do feel that it should only effect your ship efficiency or max speed for a longer/bigger range before actually letting the ship not fly straight anymore. If people wanna build strange... euh... I mean.. *cough* creative... ship (I'm really enjoying creative ship designs they should be able to without having in depth knowledge of engine tuning to only let the ship fly straight. But they should get a big hit on efficiency or max possible speed.
I also see a lot of symmetry ships that have the left/right center at the right spot, but getting the up/down center to match is really hard as it directly effects the whole ship design. I also often see users build a ship, and then start adding on guns or new modifications later on making the up/down thrust vs mass center to shift away from each other again. You can't expect every player to redesign to whole frame to keep this all centered just to keep the ship flying straight.

In my experience the centering of the two centers actually don't effect the stability of the ship to much. The controllers already seem to catch these errors pretty good in my opinion, it is just that the controller (FCU+MFC) seems to have other issues where they make designing ships really hard and unpredictable while not having a good tool to debug these issues. Even I have some ships that I just can't get to fly straight that use angled thrusters. Spending full weeks on tweaking engine setups and naming, and it just does not wanna keep flying straight in all situations, and I can't find a pattern or way to debug these issues.

Together this just really frustrates me after having already hunderds of hours in designing these ships.

So, please let me know your experience with alignment issues/tuning, and maybe a dev can pick up some feedback on this to improve the quality of the game.
I will post some tips and tricks how I debug engine setups below for people who might be interested or trying to solve alignment issues themself.

 

[ChaosRifle]

If people wanna build strange... euh... I mean.. *cough* creative... ship (I'm really enjoying creative ship designs they should be able to without having in depth knowledge of engine tuning to only let the ship fly straight. But they should get a big hit on efficiency or max possible speed.

You can. IE if you have CoT far to port, CoM far to starboard, you can have some yaw thrusters at the nose of your ship facing starboard to counteract the rotational motion the thrusters would otherwise induce.

This just doesnt work correctly always because of the issues with the MFC... Which is also the root of pretty much everything you mention here. #fix MFC's

 

[AcE Tech]

Some tips when having alignment issues on your ship :

First confirm if your setup is as intended, its basic but most problems are in this area, even though I'm sure it was good I often find myself solving problems by running the following checks :

1. Check engine names, for simple tune setups, you could just auto-rename your engines to make sure you don't have 2 engines on different part of your ship with the same name. If your doing manual naming, it helps to write down all the names and what engines group it is to prevent using the name multiple times on different parts of your ship. I often make screenshots of my ship where I put the group numbers on the engines.
   
   
   
   This way I also know how many groups I have left when building bigger ships.
   
   
2. Cable and Pipes connected, Don't expect every thruster to still be connected. Modifications on your ship could have broken cables and pipes. First go around your ship with the cable tool and check for broken cables (red boxes) and check if every thruster hardpoint has at least 1 green box of the 4 boxes visible boxes. Then do the same with the pipe tool and look for broken pipes (yellow boxes), and check if every thruster hardpoing has a maximum of 3 blue boxes (a hardpoint box does not become green like cables, but disappears when connected to a pipe).
   
   
3. Check if all are actually firing. To safe some time of checking every engine manually I like to just let the ship fly in cruise mode (in test mode or in space) with the safety line enabled, and then jump of the ship and look at all forward thrust engines from behind the ship first. See if some are not firing that you expect should fire. The manauvering thruster you can check by looking for the white particle stream or using your "U" tool when running around your ship while the ship is cruising. Most of the times you should see a current thrust value on every thruster even though it is pointed toward the front of your ship. If you discover some engines that are not showing a number write them down and check/do the following :
   - Stop the ship.
   - Rename both engine value's to some new unique name, I like to add a "d" behind it for "disabled" so it is no longer controlled by the MFC.
   - Manually set the ThrustPowerLevelxxd value to 10000
   
   
   
   - The CurrentThrust should change also to 10000 on its own and the thruster should visually fire. Also the ship should start to move.
   !! If it does not visually fire and does not show 10000 in CurrentThrust you can check the following :
   A. For all thrusters except for box thrusters, check if the hardpoint has a nail connecting the hardpoint to a beam connected to the rest of the ship. Thrusters (execpt for box once) need a bolt that connect the hardpoint to the ship frame.
   B. Check if you see ship values pop up in the left "LOG" part of the "U" tool. You should see value's pop up from other ship parts like the battery, if now it might be the cable it not actually connected to the ship cable network. It could be either a broken cable that can be found by following the cable and check for red boxes. Or if you are using ducts, it might be the duct is not proper connecting to the ship network. Ducts are harder to debug since they don't show a broken connection. The only way to test them is to add a device, like a small button (the one you can wire up) and wire it into the duct, and then check if you see data popping up in the "LOG" section.
   !! If it does not visually fire but does show "LOG" updates in the "U" tool :
   C. it means the Thruster is not actually getting propellant from the pipe. Do the same check as B. (above) but now you can focus on where the pipe is broken, or where a pipe is connecting the duct (don't forget to check the propellant tanks side going into the duct.
4. Check for thrusters that might be obstructed by other components. This problem I see a lot by ship designers asking for help. Luckily this problem is going to be much easier to figure out with an upcoming update (already live on the PTU) where you can see the thruster trails inside the ship designer. But for now (and for people in space not having access yet to a ship designer with a build ship) you can check for this problem in the following way :
   Do the same steps as written above in step 3, stop the ship, rename thrusters, manually set it to fire 10000. If everything seems to work and you get visual feedback that the engine is firing, but the ship is NOT moving at all, it means the thruster is hitting something and you should clear its thrust path better, or if that is impossible and/or your in a hurry, just leave the "d" behind the name to keep that thruster disabled and the ship should fly straight again (don't forget to manually set the thrust back to 0).

Knows Symptoms :
- Ocational "tilts" or "Bumps" when flying straight. Ship is flying straight, but occasionally doing a short "bump" or "tilt" once in a while making it still not able to fly straight over a longer flight.
= In most cases I find this is happening when an single (small)thruster is hitting against an object (problem described in step 4.)

- Stars seem to move / how to check alignment?
= The best way to check for alignment issue's is not to compare your ships with stars in the background, these seems to shift a bit over time. The best way is to search for a far away planet or moon body and aim for that. Also try to aim with something physical, laser beams seem to shift sometimes.

- Ship is suddenly not flying straight? While it always did
= 1st... is your battery filled enough? (enough power available?)
= 2nd, do you have an open door/hatch or moved a slider/hinge that you normally have in a different position?
= 3rd, Is a slider/hinge glitched or unable to fully close/open? You can check this by listening and visual checking all moving parts, or by stopping the ship and see if it start moving/rotating on its own.
= Do you have filled up your cargo. cargo can always give your ship alignment issue's that to my knowledge can only be solved with a trimming feature on the ship. (If interested in a good trimming solution, please hit me up and I might be able to help you to one).
= Are you flying at full speed? As stated in my first post there seems to be a problem where flying at different speeds can cause the ship to somehow not be stable anymore.
= Do you have damage? (both missing mass on your ship, or broken pipes/cables)
= Did you add mass to your ship? Like a crafting bench or tri-pod. (I'm unsure about this one, but it could be your own inventory adding mass to yourself and the ship.)

- Can't get my ship to fly straight no matter what I try in the designer
= Try disabling any thruster with a trail that cross over the X or Y center line (look at the front of your ship and disable all thrusters that that fire over the the mid axis of your ship, for example, a thruster firing from the top left side to the top right side and crossing the vertical center line of the ship.
= Try disabling inwards firing thrusters. Look at every thruster and imagine a line from the center of the ship toward that thruster, if the thruster is more then 90° angled from that line to the center (thus pointing slightly toward the center of the ship) disable it and see if it solves the problem.
= To be honest, this is where I'm stuck also with some ships and the reason why I started this topic to either find a solution, or to ask the devs for a bit more forgiving code

 

[BlackAndWhiteBird]

I'll just leave it here.
https://forum.starbasegame.com/thre...r-precision-efficiency-and-fine-tunning.2797/