It seems you’re still facing challenges with continuous collision detection (CCD) and trying to make static objects grabbable. I can provide a more detailed approach to help you solve the issue of collision detection while grabbing objects in VR.
Detailed Approach for Solving Collision Detection on Grabbed Objects in VR:
1. Use a Physics Handle (with Fine-Tuned Settings)
The Physics Handle is the best approach to maintain continuous collision detection for grabbed objects, as it allows you to keep the object in the physics simulation. If CCD isn’t working, using a physics handle can simulate the interaction with collision maintained.
Steps:
- Attach Physics Handle to the Grabbed Object:
- First, ensure the object has a Physics Body (e.g.,
Simulate Physics enabled).
- When the object is grabbed, attach the Physics Handle to the object. This will allow the object to stay physically simulated while being held.
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UPhysicsHandleComponent* PhysicsHandle;
AActor* GrabbedObject;
// Attach to grabbed object
PhysicsHandle->GrabComponentAtLocation(GrabbedObject->GetRootComponent(), NAME_None, GrabLocation);
- Ensure Grabbing Logic is Correct:
- When the object is grabbed, it should keep its collision active and allow interaction with other objects while being held.
Debugging Tips:
- Ensure the grabbed object’s collision type is set to
PhysicsActor, and its collision responses are set to block or overlap, depending on your requirements.
- Make sure that grabbable objects are not set to
Static while being held.
2. Use Custom Collision Profiles for Grabbed Objects
If you want more control over how collisions are handled when objects are grabbed, creating custom collision profiles for the grabbed objects might help.
Steps:
- Create a New Collision Profile for Grabbed Objects:
- In Unreal Engine, you can create a Custom Collision Profile for objects that are grabbable.
- When the object is grabbed, switch the collision profile to allow continuous collision interactions.Example of switching collision profile when grabbing:
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// Grab the object
UPrimitiveComponent* GrabbedComponent = GrabbedObject->FindComponentByClass<UPrimitiveComponent>();
GrabbedComponent->SetCollisionProfileName("GrabbableObject");
- Set Overlap Responses:
- Modify the overlap response to ensure that it reacts to other objects while being held, preventing collision detection from being disabled.
3. Enable Continuous Collision Detection for Specific Objects
If you can’t use CCD globally for all objects, consider manually enabling it for the grabbed object.
Steps:
- Enable CCD for the Grabbed Object:
- Set
bUseContinuousCollisionDetection to true for the grabbed object to ensure continuous collision detection is enabled while the object is being held.
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UPrimitiveComponent* GrabbedComponent = GrabbedObject->FindComponentByClass<UPrimitiveComponent>();
GrabbedComponent->SetUseContinuousCollisionDetection(true);
- Reset CCD when Released:
- Once the object is released, you can reset the CCD setting to its original state.
4. Adjusting Object Physics When Grabbed
You can experiment with temporarily adjusting the physics behavior of the grabbed object to keep it in a dynamic state, allowing continuous collision interactions.
Steps:
- Enable and Disable Physics While Grabbing:
- Enable physics when grabbing an object and disable physics while holding it, but still keep the collision responses active.Example:
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UPrimitiveComponent* GrabbedComponent = GrabbedObject->FindComponentByClass<UPrimitiveComponent>();
// Enable physics when grabbing
GrabbedComponent->SetSimulatePhysics(true);
// Disable physics while holding
GrabbedComponent->SetSimulatePhysics(false);
- However, make sure the collision response is still set to overlap or block during the holding phase.
5. Event-Driven Collision Switching
You can switch the collision detection dynamically based on the object’s state (held or not). Using event-driven logic for switching collision profiles when grabbing or releasing an object can offer a more tailored approach.
Steps:
- Switch Collision Profiles on Grab/Release:
- When grabbed, set the object’s collision profile to something like
GrabbableCollision, which is more suitable for the interaction.
- When released, revert it to the normal profile.Example:
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if (bIsGrabbed)
{
GrabbedComponent->SetCollisionProfileName("GrabbableObject");
}
else
{
GrabbedComponent->SetCollisionProfileName("Default");
}
6. Testing and Debugging
Test different settings with collision logs and debug drawing to ensure that the collision is happening as expected. Use Unreal Engine’s built-in debugging tools to log collision events when objects are grabbed and released.
Conclusion:
- Physics Handle is the most reliable method for maintaining collision while grabbing objects in VR.
- Adjusting collision profiles and CCD settings for specific objects can improve the interaction.
- Consider an event-driven approach to dynamically switch between collision profiles based on whether an object is being grabbed.