Hi,

The difference between a short ray and long ray is almost entirely a performance issue: the longer the ray is the more objects it could potentially intersect which means Havok has to do more work. When a ray cast happens, it first does a broadphase check to see what objects could potentially get intersected, and then it does the individual ray-to-object intersection tests sorted by distance from the start of the ray. So limiting the number of potential objects to check can result in some pretty major performance wins. If the volume in which you want to do the intersection test is limited and known, then you could use a hkpPhantom--this allows you to define a volume and only the objects inside that volume are raycast against. In your case, you could attach the phantom to the character so that it keeps track of only what's around the character. See PhantomObjectDemo for more information (.\Demo\Demos\Physics\Api\Dynamics\Phantoms\PhantomObject\).

I don't think hkpShape::castRay is quite what you want because it doesn't take into account any of the other objects in the scene. But I dont have a really clear picture of what youre trying to accomplish, so if Im not answering your question, please give some more details on what exactly youre trying to do (e.g. are you using the mouse to pick up the object?).

Best regards,

--Joel

Hi, The immediate problem here is forcing the position directly outside the physics step like you said. The approach you want to take instead is to apply an impulse or force such that the box will move to the point you want within the next frame. I see you're already modifying the velocity, so you could just add to that : linearVelocity += ( boxPos - boxCurrentPos ) / timeDelta That said, the best thing to do here would be to encapsulate this behavior inside an hkpAction (Docs: Havok Physics/Hello World!/Populating and Updating the World/Actions). This way Havok will execute your code to modify the velocity within the physics step and it will also give you the correct time step information. All you need to do is create a new type of action with your code in the applyAction function. Then when you want to start controlling the object just create an instance of this action, set the camera and the rigidBody you want to control and call world->addAction(). To drop it, call world->removeAction(). The docs and demo (Demo/Demos/Physics/Api/Dynamics/Actions/UnaryAction) actually make an anti-gravity action (with a cool hover/floaty effect), which looks especially relevant :) Cheers, Tyler