Lineargravityfield() Is Not Affecting Physics Bodies in the Scene Scenekit

linearGravityField() is not affecting physics bodies in the scene SceneKit

Set the "downGravityCatagory" bit mask on the node:

dice.categoryBitMask = downGravityCatagory;

the physics's categoryBitMask is for physics collisions only.

Physics forces not affecting dynamic body Scenekit

For physics to simulate the node needs a physicsShape assigned, which is achieved with;

_secondNode.physicsBody.physicsShape = [SCNPhysicsShape shapeWithGeometry:[SCNSphere sphereWithRadius:2] options:nil];

Make particle system only be affected by certain categories of physics fields in SceneKit?

Ok, I don't know how I overlooked this, but the answer is right in the documentation for SCNPhysicsField's categoryBitMask property.

To determine whether a field affects the particles spawned by an
SCNParticleSystem object, SceneKit performs the same check using the
categoryBitMask property of the node containing the particle system.

Making physics bodies responsive to fields but not to other physics bodies

You should set

body.physicsBody?.collisionBitMask = 0

collisionBitMask - A mask that defines which categories of physics bodies can collide with this physics body. IF the value is not set your PhysicsBody collides with every other PhysicsBodies, If value is set to 0 your PhysicsBody do not collide with other PhysicsBodies

I you set collisionBitMask = 0 your body node will go through all other nodes, if you whant it to collide you need to set node physicsBody?.collisionBitMask (for example if you whant your node to collide only with ball and wall physicsBody?.collisionBitMask = kCategoryWall | kCategoryBall)

I hope it was helpfull

Can't prevent physics field from interacting with particle system using category bit mask

I've discovered that the category bit mask cannot be set on the physics field within the scene graph builder, it isn't exposed. It must be set programatically. I was setting the mask on the physics field node, hence why it wouldn't work.

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