Wobbly Base Woes

[ThomJ]

To be more specific, wobbly self-destructing base woes. My Minmus mining base has been waiting very patiently to come online and start sending interplanetary missions, but trying to build it has been a nightmare. Beginning with the landing leg rotation bug that prevented (or at least made it very difficult) to place landing legs the way I wanted to, followed by the undocking bug which basically super glued the fuel storage tank to the skycrane in LMO and now my most feared bug has returned to lay waste to this poor outpost. I haven't been able to nail down what exactly causes it, but it seems if there's too much mass spread out over too long a distance (such as 4 full large ore tanks and 16 drills placed far away from each other, see included image) then any tiny nudges or oscillations tend to constructively interfere and basically build up until the entire structure tears itself asunder. The docking ports also seem to contribute to the instability of the whole system. Assuming those are the reasons this is happening, I could attempt to redesign the whole base by using the Sr sized docking ports and keeping the mass close to the center, but that's just a theory and it may not even work. 

Why is this bug still in the game? I seem to recall having this issue years ago. And do we know what exactly causes it?

KSP 1.1.3 1289

  

 

Edited July 20, 2016 by ThomJ

[sal_vager]

Hi @ThomJ, does this issue occur with the solar panels retracted?

[Majorjim!]

Just now, sal_vager said:

Hi @ThomJ, does this issue occur with the solar panels retracted?

Good thought Sal, I too have seen panels wobble alarmingly. My guess would be that too plus the leg issues that cause a feedback loop type effect tearing the base apart. It is far worse on low grav worlds.

[sal_vager]

Actually no, I ask as there's two separate issues that I know of that could be at play here.

The first is a problem with PhysX and it has been present in KSP for a long time, there doesn't appear to be a fix yet or a means to damp it out that actually works.

For a fun time, place a Mk1-2 pod (though this works with most parts), place one M200 I-Beam on the top node, and then surface attach a further 5 or more I-Beams on the side of the first beam (It does not matter how you do this)

Or load this craft.

This works with all parts with Physics = 0 if used in enough quantity and is dependent on mass, so a large ship that uses its fuel can later show this problem.

Struts completely eliminate it.

 

The second issue is with the wheels, there is a problem when using more than 20 wheels on a vehicle in Unity5+, and craft with more wheels/legs will display some unwanted behaviour.

To see this just dock 3 crater crawlers in the SPH and launch it.

It looks like a limit in Unity, much like the 20 button limit on controllers and the 20 layer limit in the Unity editor, I'd be interested in knowing how other build-your-own craft games that are made in Unity manage to get around it, such as TerraTech and Simple Planes.

That's if they do, I've not played them yet to check.

[OrbitalBuzzsaw]

I'd not know, my bases are all KPBS which works good. Perhaps try using aircraft wheels pointed sideways?

Edited July 20, 2016 by OrbitalBuzzsaw

[Majorjim!]

Just now, sal_vager said:

Actually no,

No to what?

 

[sal_vager]

48 minutes ago, Majorjim said:

My guess would be that too plus the leg issues that cause a feedback loop type effect tearing the base apart

No to this, it's one or the other, the legs don't feedback into the PhysX issue and vice versa.

[Majorjim!]

6 minutes ago, sal_vager said:

No to this, it's one or the other, the legs don't feedback into the PhysX issue and vice versa.

Right ok, I worded my reply incorrectly then, one or the other. 

[sal_vager]

No worries, you were not to know

[igor290506]

1 hour ago, sal_vager said:

Hi @ThomJ, does this issue occur with the solar panels retracted?

Hi sal_vagar is fellipe falange alredy singed off?

47 minutes ago, sal_vager said:

Actually no, I ask as there's two separate issues that I know of that could be at play here.

The first is a problem with PhysX and it has been present in KSP for a long time, there doesn't appear to be a fix yet or a means to damp it out that actually works.

For a fun time, place a Mk1-2 pod (though this works with most parts), place one M200 I-Beam on the top node, and then surface attach a further 5 or more I-Beams on the side of the first beam (It does not matter how you do this)

Or load this craft.

This works with all parts with Physics = 0 if used in enough quantity and is dependent on mass, so a large ship that uses its fuel can later show this problem.

Struts completely eliminate it.

 

The second issue is with the wheels, there is a problem when using more than 20 wheels on a vehicle in Unity5+, and craft with more wheels/legs will display some unwanted behaviour.

To see this just dock 3 crater crawlers in the SPH and launch it.

It looks like a limit in Unity, much like the 20 button limit on controllers and the 20 layer limit in the Unity editor, I'd be interested in knowing how other build-your-own craft games that are made in Unity manage to get around it, such as TerraTech and Simple Planes.

That's if they do, I've not played them yet to check.

then ksp pach 1.1.4.1390

[ThomJ]

@sal_vager I just tried it with the solar panels retracted it had no effect what so ever. Just a quick note too that the picture provided is when the base is stable. As soon as the leftmost mining module is docked, that's when things get out of control. I had to clip some parts (more specifically the docking port and reaction wheel) into the rover in order for it to fit under the modules. Perhaps the clipping is to blame? I've heard of clipping being an issue before. I guess the too many wheels/legs limit makes sense too as this is never an issue until I add this last module.

Edited July 21, 2016 by ThomJ

[sal_vager]

It can be an issue yes, though it seems to be random and the same ship rebuild can fail to show clipping issues.

Can you upload the save for us to try it?

[Guest]

I have not had good results with crafts that combine wheels and legs with docking ports. Bouncing and exploding occur.

[ThomJ]

Sorry i'm a noob when it comes to uploading save files, how do I do such things? Also do you only need the persistent file?

[Guest]

On 7/22/2016 at 10:56 AM, ThomJ said:

Sorry i'm a noob when it comes to uploading save files, how do I do such things? Also do you only need the persistent file?

A post like this is hard to see unless you use a quote or a shout like this : @ThomJ. As far as your question about save files, I usually use google drive. You can upload the file to google drive and then post the link here. There are other ways to do this, nearly as many ways as there are to skin a cat. Include one persistence file, the most recent relevant one. You may also want to include the ships folder which contains you craft files, not sure if that is necessary or not, never tried it. Same with subassembliues if you use them, again, not sure if that is necessary.