How do I stop suspension freaking out?

[Grth]

Hi all,

I'm having an issue with my suspension. I don't feel like I'm doing anything outrageous with it, but when I drive, it starts shaking like crazy, and eventually flips around. I've configured it a couple of different ways with the same results.

For the front wheels I've got a double wishbone:
https://steamcommunity.com/sharedfiles/filedetails/?id=1525786154
https://steamcommunity.com/sharedfiles/filedetails/?id=1525786398

And at the back, a swingarm type thing.
https://steamcommunity.com/sharedfiles/filedetails/?id=1525786614

Both are pretty simple, a single shock with rotators top and bottom, hooked up to pivoting arms. However, here's what happens when I drive a bit and then take screenshots. In motion, the springs are freaking out, shaking and shuddering everywhere to the point of being a blur:
https://steamcommunity.com/sharedfiles/filedetails/?id=1525787754
https://steamcommunity.com/sharedfiles/filedetails/?id=1525788021

And eventually everything hyperextends, and it all kind of collapses on itself.
https://steamcommunity.com/sharedfiles/filedetails/?id=1525788261

Any suggestions on what's happening? I feel like it's a problem with the game, but I'm hoping someone can suggest a workaround, like rewelding certain joints, or building things in a specific order.

Thanks!

[Vajdani]

you cant stop it. the devs have to stop it

[suicidal.banana]

My best guess is your missing some welds, while theres definatlly something to be said for suspensions and bearings having a love-hate relationship, what you describe really shouldnt be happening, just incase this isnt a missing weld, i figured i should write some step by step for finding out issues with vehicles, as this will happen more as you build more, some of these tricks are pretty old and im not sure if they're still relevant, but i still use them.

Lets go trough a list of things to check/do:
1 - Does it have any missing welds?
2 - Did you connect any of the bearings that should be free motion to anything?
3 - Do you use any modded parts on the vehicle? (doesnt look like it but just to be sure?)
4 - Did you build the car in an older version? or downloaded it from an old workshop upload?
5 - Did you try adding some weight too the car? those pipes you use weigh bscly nothing.
6 - Does the car fit together in as few pieces (grids) as possible if you remove all bearings?
7 - Did you try lowering the amount of bearings?
8 - When it goes wack, look at all moving parts, are any intersecting/did any go trough other parts?
9 - Do all the rotating parts have enough room to do so?

Below a list of details/todo's based on the above, included pics for some.
If you're still having troubles after going trough this list, upload your contraption to workshop, set it to unlisted and share the link here and/or with the devs.

[suicidal.banana]

-- (1) Welds ---------------------------
Place your car on a lift, whip out the welder tool, and look at your car, using the white highlight of the welder tool check that everything is connected to eachother like it should, if its not (like in the below picture), you click on one of the white highlighted bits, hold down the mouse, aim at another bit of the car that should be part of the same thing, and let go, now these parts are welded together to become one.
Example of missing weld: https://i.imgur.com/TwKvRml.jpg (top-right corner isnt connected to rest of the bar)
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-- (2) Bearing connections ---------
For what your trying to do, its super important that all bearings in your suspension setup are free movement ones, if you connected any of these to your motor or seat or anything else thats why stuff is going south.
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-- (3) Mods -----------------------------
Sadly there are mods that seriously break things like suspensions etc, so if you have any mods enabled at all, disable them and see if it changes anything, you can do this in the load game screen when you select the world, mod-list is on the right before clicking load.
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-- (4) Old contraption / World -----
Some older contraptions are for whatever reason buggy af, rebuilding them will fix, also make sure your not in a world you've been using for months as you may have forgotten about big laggy projects outside of your view distance, ive had that too :P
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[suicidal.banana]

-- (5) Minimum Weight --------------
The physics system is basic, it might be freaking out because the car is too lightweight, dont ask me the exact numbers because i really dont know, but depending on the amount of suspensions used, they will reach a point where they are too strong, either fiddle with the suspension-strength-settings or add some weight to the vehicle
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-- (6) Amount of pieces/grids ------
Perhaps most important, you should make sure it uses the least amount of pieces/grids possible, what this means is that you should connect any mirrored pieces to eachother to save resources, or (since that sounds sorta weird) look at the below two pictures, ive given each piece / grid a different color to better illustrate what im trying to tell ya.
This needs extra processing power / more chance for bugs: https://i.imgur.com/v3rLGSO.jpg
This is optimized & has less chance for bugs: https://i.imgur.com/FkQs5Iy.jpg
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-- (7) Amount of bearings ----------
Another one to keep in mind is that each connected bearing requires more processing power, so something to keep in mind for bigger contraptions, i tend to double up my bearings too and in general it should be fine, but when your making something with alot of bearings you will want to stick to 1 bearing for each pivot point. This also very much relates to the amount of processing power you have available, on a beefy up to date machine you can have a bunch more bearings before things get laggy then you can on a few years old machine, something to keep in mind when downloading some of the workshop things.
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[suicidal.banana]

-- (8) Parts going trough others --
This is a fun one, theres a bug in the physics engine of scrap mechanic where model-vs-model collisions dont always work out when high speed and/or suspensions are involved, and models intersect or even go trough each-other. The best workaround i've found is to use blocks one the parts that collide, for cars i usually only put the blocks on the chassis/body-frame and then use those as starting points for bodywork, see the below pictures for examples of what i mean with the model/block vs model/block collisions. It all depends on speed to decide what to use, low speeds model-vs-model is fine, medium to high speeds one side model one side block, very high speed both sides blocks. This only works with actual ('strong') blocks, bigger or cube-shaped models will still intersect at speeds!
This can cause troubles above low speed: https://i.imgur.com/h1oQGdd.jpg
This can cause troubles above high speed: https://i.imgur.com/xtiLTRd.jpg
This is best but looks worst on a bare frame: https://i.imgur.com/RrWPRPG.jpg
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-- (9) Rotating parts -----------------
Sorta related to item 8, rotating parts can intersect too, and this should also be avoided. Whats explained in item 8 applies here aswell, so intersections will depend on model/block vs model/block, for example a door of blocks (wood piece in pics) will get pushed out of position by intersecting the wall of blocks, while a model (metal bar in pics) might go straight into a block. Best way to deal with this is to just be aware of it, either leave gaps so theres nothing to intersect, or make your contraption with some of the more block-shaped models that have gaps, see below pics for example.
When you dont account for it, stuff intersects: https://i.imgur.com/hYF9TQe.jpg
What you want to do is this: https://i.imgur.com/ucbzq1n.jpg
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Hope this helps, at the very least i've finally written a how-to to keep pasting on these kind of threads :3 (and i really wish we could make longer posts lol)

[Grth]

suicidal.banana - you're a champion. I'll work through the checklist and troubleshoot. I really appreciate the detail, and the time you've taken to help out.

[suicidal.banana]

Your welcome, hope you managed to solve your problem :)