You are correct. The spike happens only on structural changes to the mechanism (adding removing a body or constraint).
In your case you have a complex mesh of 324 rods. It will kill your performance for a frame.
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In my case I am not adding or removing parts from the web of rods and balls, so what structural changes to the mechanism are happening that causes these lag spikes?
If you don’t add or remove constraints or bodies, then it will happen only once, when you create the mechanism. Basically the engine has to make a complex analysis of your mechanism that grows exponentially with the number of cycles you have in your constraint graph. In your example you have 18 parts connected by over 300 rods.
The question I have is whether a mechanism like that is necessary?
This works great with large scale mechanisms. Definitely more stable, especially with PrismaticConstraints and HingeConstraints. Great work!
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I am not really trying to argue that my complex web of constraints is a common and necessary mechanism. I’m just highlighting a repeating lag spike problem that upon further inspection seems to occur when the network ownership of the mechanism changes, causing a redundant complex analysis of the mechanism.
Yes changing network ownership of the mechanism would do this re-computation too. Good point! But since this seems to happen only for extremely complex mechanisms that won’t appear in any real game - as far as I know - I wouldn’t worry about this performance issue until later.
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Alright thanks for taking the time to respond to my questions
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It’s not the total number of constraints but the complexity of the constraint graph that matters (number of constraints / number of bodies). In your case you have more or less the same amount of bodies than constraints.
Nice model btw!
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I’m very keen to jump on that… for testing purposes of course. Link?
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Not sure if this is related to the same thing. But with the old version and the new test version of studios this happens. https://youtu.be/eTdNNmgrQ8Q?t=620 I can’t figure out if its constraint related or just bad physics. Because I can rebuild the track 8327532985 times make it perfectly smooth but cars still bounce into the air over different areas. Originally I thought it was the constraints dying but after constantly testing and stuff it only happens when driving over new track segments.
Thanks for the great feedback so far on the beta build everyone! In addition to posting repro levels/instructions for any problems you encounter, please also post your success cases here. We definitely want to see those as well!!
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My cars still don’t seem to be able to steer properly in the place with this system enabled. The cars just sort of lift off the ground and loose all speed whenever I try to steer which doesn’t happen in any other places that don’t have this enabled.
This is what it currently looks like:
@chefdeletat That repro I sent last time still reproduces this in case it’s needed
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Could you enable the updates on this place please?
Thanks for this find! I’m still trying to figure out what’s going on with this model. Will keep you updated
It is already enabled on the place ID 2161309219.
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The reports are overall positive and we haven’t found any other bugs.
We are going to wait few more days and enable this feature globally sometimes next week.
Thanks a lot for beta testing this for us!
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Enabled. Please report any issues.
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