Search found 4435 matches

by Norbo
Fri Jan 24, 2020 12:39 am
Forum: Questions and Help
Topic: Rotating parts of compound body
Replies: 29
Views: 270

Re: Rotating parts of compound body

So how can I fix this? Is there a demo I can look at to see what I should be assigning the filters to? The CarDemo (through the SimpleCar), RagdollDemo, and TankDemo (through the Tank) all make use of SubgroupCollisionFilter. The idea is that a body can belong to a group, and within the context of ...
by Norbo
Thu Jan 23, 2020 1:01 am
Forum: General
Topic: Unity and Bepu v2 notes
Replies: 23
Views: 10524

Re: Unity and Bepu v2 notes

There's the thread cosmixy posted earlier, but I'm not aware of any existing issues to vote on (though that doesn't mean they don't exist!).
by Norbo
Thu Jan 23, 2020 12:29 am
Forum: Questions and Help
Topic: Rigidbody sticking to mesh like fly paper
Replies: 4
Views: 49

Re: Rigidbody sticking to mesh like fly paper

Hmm... careful, monsters may still lurk. Oversubscription can definitely hurt performance, but it typically manifests as a gradual degradation. For example, if I launch 8 jobs that each use every reported hardware thread (so a total of 16 threads per physical core on 2-way SMT), it'll be worse than ...
by Norbo
Wed Jan 22, 2020 11:54 pm
Forum: Questions and Help
Topic: Collision points
Replies: 1
Views: 15

Re: Collision points

The engine doesn't store anything it doesn't use internally, so the only place contacts are 'stored' is a processed version in the solver's prestep data. Custom INarrowPhaseCallbacks can be used to collect contact information as it is generated by the narrow phase. Some demos, like the ContactEvents...
by Norbo
Wed Jan 22, 2020 11:36 pm
Forum: Questions and Help
Topic: Rotating parts of compound body
Replies: 29
Views: 270

Re: Rotating parts of compound body

Here's the reproduction in a relatively bare bones console app. The collision is being filtered out. SubgroupCollisionFilters are being used in AllowContactGeneration, but the filters are never assigned to anything. The value they happen to have causes the callback to return false. I did however no...
by Norbo
Tue Jan 21, 2020 10:19 pm
Forum: Questions and Help
Topic: Rigidbody sticking to mesh like fly paper
Replies: 4
Views: 49

Re: Rigidbody sticking to mesh like fly paper

Given the fact that it happens inconsistently and only on some testers, environmental issues or nondeterministic issues are most likely. I'd recommend tracking down a few leads: 1) Gather information on operating system/CPU. If possible, find another tester with the same configuration to see if it r...
by Norbo
Mon Jan 20, 2020 8:16 pm
Forum: General
Topic: Unity and Bepu v2 notes
Replies: 23
Views: 10524

Re: Unity and Bepu v2 notes

3000x slower is pretty wonky. I'd first rule out benchmark problems like running in debug mode, measuring the cost of JIT compilation, and so on. I don't think that'll fully explain it, though. The GC alloc in particular makes no sense- that function definitely should not allocate. It may imply that...
by Norbo
Sat Jan 18, 2020 11:30 pm
Forum: Suggestions
Topic: Make a public discord server
Replies: 3
Views: 91

Re: Make a public discord server

Well, I guess I'll give it a shot:
https://discord.gg/ssa2XpY

I'll still be mainly here on the forum (and on github) for long form stuff, but I might pop in occasionally.
by Norbo
Sat Jan 18, 2020 11:26 pm
Forum: General
Topic: Optimizations available for terrain type meshes?
Replies: 1
Views: 39

Re: Optimizations available for terrain type meshes?

Mesh shapes use a tree (specifically, a binary tree created by SAH sweep builder) to accelerate collision testing. It performs a log(n) query to find the triangles with overlapping bounding boxes. Only those triangles are tested. Terrains do indeed have regularity that can be exploited to help with ...
by Norbo
Thu Jan 16, 2020 10:23 pm
Forum: Questions and Help
Topic: Rotating parts of compound body
Replies: 29
Views: 270

Re: Rotating parts of compound body

Considering I haven't added anything, could this still be the issue? It doesn't make sense to me that collisions would work, except for this particular collision... Some demos callbacks have collision filtering, some don't. If the callbacks all return only true, you can be sure that it's unrelated....
by Norbo
Thu Jan 16, 2020 12:50 am
Forum: Questions and Help
Topic: Rotating parts of compound body
Replies: 29
Views: 270

Re: Rotating parts of compound body

I haven't set anything up with collision filtering (besides removing cannonballs from the simulation when they hit another body)—how can I find out if this is the culprit? You would have had to implement some form of collision filtering in the INarrowphaseCallbacks by returning false from the relev...
by Norbo
Wed Jan 15, 2020 10:46 pm
Forum: Questions and Help
Topic: Rotating parts of compound body
Replies: 29
Views: 270

Re: Rotating parts of compound body

Just to clarify, do the weights actually affect the final mass of the compound (if I'm scaling the inertia), or do they only make a difference relative to each other? Basically, can I just give each child shape a weight of 1 and then scale the inertia to give the compound a mass of 500, even if the...
by Norbo
Tue Jan 14, 2020 11:37 pm
Forum: Questions and Help
Topic: Rotating parts of compound body
Replies: 29
Views: 270

Re: Rotating parts of compound body

Are the child shape weights fairly uniform, so that the inertia tensor is reasonable for the actual size of the boat?

As always, the quickest way for me to figure out this kind of issue would be to reproduce it in the demos with a stripped down example for me to look at.
by Norbo
Tue Jan 14, 2020 9:38 pm
Forum: Questions and Help
Topic: Rotating parts of compound body
Replies: 29
Views: 270

Re: Rotating parts of compound body

A sufficiently small inertia tensor could be at fault, yes. It could also be that the goal position of the capstan is partially embedded in the ship. Stiff constraints fighting each other with a long lever arm relative to inertia could cause tornadoship.
by Norbo
Tue Jan 14, 2020 9:15 pm
Forum: Questions and Help
Topic: Rotating parts of compound body
Replies: 29
Views: 270

Re: Rotating parts of compound body

If for example I wanted the collider to rotate around its local Y axis and to be locked in place at <0,1,1> in the ship's local space, what do I need to set the offsets to? Provided you want the anchor of the constraint to be at the capstan's center of mass, and assuming the ship is body A, then Lo...