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Shawn876

Member Since 26 Sep 2006
Offline Last Active Oct 29 2012 07:57 PM

Topics I've Started

Transforming a large number of 3D points

09 October 2012 - 01:07 AM

Hi,

I currently apply a matrix transform a series of 3D points, which is quite expensive in terms of processing time.

Is it possible to transform just the extent points (I create a bounding box which encapsulates the points) and do some kind of linear interpolation to shift all the points without having to apply the transform to each of them?

Thanks.

Cubic splines and camera movement

10 October 2011 - 04:00 AM

Hi,

I am in need of a very specific kind of spline. Recently I have been working with equal distanced cubic hermite splines for my camera movement, which works well. However, this kind of spline will not take into account my cameras current lookat direction. It will simply take into account the control points and start / end tangent vectors from those points. I need a spline that will also take into account the direction a control point is currently 'facing'. (related picture attached).

The effect I am looking for is similar to how google earth moves its camera between bookmarks.

Is there an easy way to achieve this? Or will it just require me figuring out / inserting alot more control points manually?

Any ideas on how to start on this would be helpful.
Thanks.

PhysX NxCapsuleController and upDirection

06 October 2011 - 03:16 AM

Hi,
I am currently trying to implement something similar to the 'SampleCharacterController' example in the PhysX SDK with a capsule controller.

Background:

I have multiple PhysX scenes in my spherical world, spaced out via a patch system (sections of the world). These scenes do not use fixed axis systems (i.e. have arbitrary up vectors which are not axis aligned).
I have created terrain PhysX meshes for all of the terrain in my scenes, and I have a vehicle controller which works quite well using them.

The problem:

I noticed there was an 'upDirection' required to be specified in the descriptor of the capsule controller.
When i set the upDirection to a specific aligned axis (NX_X/ NX_Y/ NX_Z), I notice that my controller will hit the terrain tri-meshes and get resolved strangely (trying to move along the real Y axis I assume?).
The capsule itself when visually displayed in debug mode (and using one of the fixed up axis enum's) will be on an undesirable angle.
The gravity vector for each scene, is resolved to be the scenes origin on the surface, heading towards the centre of the planet.

descriptor setup code example:
NxCapsuleControllerDesc desc;
desc.position.x = scenePosition.x;
desc.position.y = scenePosition.y;
desc.position.z = scenePosition.z;
desc.radius = 1.0f;
desc.height = 2.0f;
desc.upDirection = NX_Y;   <------- Issue here
desc.slopeLimit = 0.0f;
desc.skinWidth = 0.0001f;
desc.stepOffset = 0.5f;
desc.callback = NULL;

Questions:

Why can't the controller resolve terrain penetration by just using the scenes current gravity vector?
Is there a way I can use this controller with this arbitrary no axis aligned system?

Thanks.

PhysX - moving actors between scenes

27 June 2011 - 07:21 PM

Hi,

I'm currently using PhysX 2.8.1, and I have multiple Physx 'scenes' in my application (due to floating point precision issues its impossible to have only 1 scene). At certain times I require the ability for actors to be taken out of one scene and placed in another, is there any easy way to do this? I couldnt find any way to remove an actor (and its body, and its shapes) from a scene 'intact' without having to call 'releaseActor' to remove it from the old scene.

The only other way I was thinking was to save out the descriptors for the actor / body / shapes manually and recreate the actor for the other scene, then release the actor from the old scene. This seems rather time consuming.

Any ideas?

Thanks.

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