Offset BoxShape with shapes not around origin.

[arkiruthis]

I'm using Jolt just for collisions at the moment. During my own physics update, I use body_interface.SetPositionAndRotation(...) to update objects.

The models I export are sitting on the Z plane, rather than centered on it. This means their center of volume is vertically above the origin.

I'm suspect I'm misunderstanding OffsetCenterOfMassShapeSettings and I've been looking the Tank Vehicle Test to try and figure out how this is intended to work.

The problem I'm having is that it doesn't matter what I put in as a Vec3 offset to the offset creation settings, the bounding box remains centered around the local origin?

Creation of offset body:

    JPH::OffsetCenterOfMassShapeSettings offsetMassShape(Vec3(0, -halfExtents.GetY(), 0), new BoxShape(halfExtents));
    JPH::Shape::ShapeResult result = offsetMassShape.Create();
    if (result.IsValid())
    {
        JPH::ShapeRefC collisionShape = result.Get();

        // Create body creation settings
        JPH::BodyCreationSettings body_settings(
            collisionShape,
            nda::ToJolt(newPosition),
            JPH::Quat::sIdentity(),
            mesh.isStatic ? JPH::EMotionType::Static : JPH::EMotionType::Dynamic,
            mesh.isStatic ? Layers::NON_MOVING : Layers::MOVING);

        body_settings.mUserData = static_cast<uint64_t>(static_cast<uint32_t>(e.ID()));

        e.MutableTransform().bodyID = m_physics->CreateBody(body_settings);
    }

In my physics update:

            auto transformsView           = m_registry.view<nda::TransformComponent>();
            auto joltPhysics              = m_physics->System();
            BodyInterface &body_interface = joltPhysics->GetBodyInterface();
            std::for_each(
#ifndef __APPLE__
                std::execution::par,
#endif
                transformsView.begin(),
                transformsView.end(),
                [this, &body_interface, &transformsView](auto e) {
                    const auto &transform = transformsView.get<nda::TransformComponent>(e);
                    const glm::vec3 &pos  = transform.Position();
                    const glm::quat &q    = transform.Orientation();

                    body_interface.SetPositionAndRotation(
                        transform.bodyID,
                        Vec3(pos.x, pos.y, pos.z),
                        Quat(q.x, q.y, q.z, q.w),
                        EActivation::DontActivate);
                });

[jrouwe]

OffsetCenterOfMassShape only offsets the center of mass (and not the shape), you want to use RotatedTranslatedShape instead.

[arkiruthis]

Thank you! Apologies, I should have created this as a discussion not an issue.