Tank Chassis =/= Constraint Chassis

Impressive tank suspension and steering!

Thankuvedymuch chefdeletat, but obviously couldn’t have figured it without NWSpacek and StratoVector,

Learned a lot about Constraints from that, working on a construction site with front end loader, dump truck and hopefully a bulldozer next.
An original version I was working on got stuck when I was first trying to work with various Body forces but the issue was mostly the ‘rocks’ acting stuck. Think I got that fixed now.
Now how to figure out how to keep a vehicle with multiple Constraints from exploding occasionally…
Working with steering and having issues so I went back to Scripted Weld joints for the steering on the dump truck:

Yeah explosions are a bit of a problem. We have a fix in the pipeline. For now here are some tips to prevent them:

  1. the constrained parts must be perfectly aligned. For example if you have two hinges between tow parts, and the axes are slightly misaligned, it will contribute to instabilities
  2. springs must have a finite MaxForce set to something reasonable. Spring tend to be unstable, clamping their forces prevents the instabilities from exploding.
  3. avoid high mass ratios:
  • avoid heavy body on very light wheels or on light tread
  • tiny light knuckle in the suspension (part between body and wheel)

Hope this helps.

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Nice to hear you’re working on this!
It seems to be more of a spawning issue after the weld scripts unanchor the Parts.
The front end loader and dump truck usually spawn fine, and if they do they work great after that. Both have weld scripts in them with Anchored Parts for most of the chassis, but there are some unanchored unwelded Parts in the suspension.
I tried saving the Model in Studio Test mode after the weld scripts had run but it seemed to make it worse.
The Springs are usually set somewhere below 10,000 MaxForce. The dump truck body Parts are set to Density=0.01 but the wheels are Density=4. Going to try that with the loader too. I try to get away with single HingeConstraints instead of multiple HingeConstraints in line with each other.

On another note I tried making a hanging ladder (like a chain type ladder) out of solid Part rungs with Constraint Hinges between them, then Rods, then Parts with Ball in Socket ends. Wow that was a lot of bouncing and exploding in each case!

Yeah there are some spawning issues, but I’m not an expert on these. Usually I people anchor the mechanism during the welding phase. Also there are some timing issues during instancing and one needs to wait a frame or so.

I can imagine a complex ladder having these sorts of problems. Currently the constraints can’t handle very long/complex constraint trees but we are working on this.