[ODE] 2 more quick ODE newbie questions.

Jeremy Roberts jroberts at digipen.edu
Tue Aug 28 01:44:36 MST 2007


Hello,
     I have 2 more quick questions from an ODE newbie.

     1)  I am trying to figure out exactly what data needs to be stored in object instances that use ODE.  For all intents and purposes I would like to simply be able to store the dBodyID.  Then, during instance destruction call something like dBodyDestroyGeoms(dBodyId) and dBodyDestroyJoints(dBodyId).  Therefore an object instance would only require storage of a single ID (the dBodyId).  The destruction pipeline seems a little un-user intuitive.  Does one really have to store ALL geomsIDs, all JointIDs and all dBodyIDs for any given object instance?  If this has been covered somewhere I apologize.  I am new to using ODE.  
   
     2) I know to create spaces encompassing objects with multiple to many geoms but am still curious how important it is to create a hierarchy of spaces for a mid sized outdoorsy game.  Is the quad-tree enough?  

     Thank you for your help.
     Jeremy (grill8)
  ----- Original Message ----- 
  From: Jeremy Roberts 
  To: ODE at ode.org 
  Sent: Monday, August 27, 2007 7:44 PM
  Subject: New to ODE (a few more basic questions).


  Hello,
       Thanks to all who responded to my previous post.
  To all - 
       I am new to ODE and have a few more basic questions.  I am trying to figure out an effective pipeline for generation of ODE data and would love to hear input if there is a more effective pipeline than the one I outline below.

       The steps I am thinking of using to create physics data for my 3D app are as follows.

       1) Use a modeler (in my case Milkshape) to create meshes that correspond to the geom/space hierarchy associated with the object.
       2) Create a .x file and hard code that information generated from the modeler radii / extents / rotations / positions etc. in the file.  Also hard code the mass/inertia matrices etc.
       3) When an object is loaded, parse the associated .x file and read the associated physics traits.
       4) Insert them into a globally initialized quad space.

  Other questions:
       1) Is there a way to create the geoms directly from the meshes generated in the modeler?  As far as I know DirectX only can create AABBs and Spheres.  I do not know of a way to create non-AABBs or cylinders directly from DirectX meshes hence the need to hard code that data in the file.  The mass/inertia matrices would need to be hard coded regardless.

       2) For an outdoors 3D app is there a need to create a space hierarchy (other than the one for each object) besides the Quad Tree?

  Thank you for your help.
  Jeremy

  A.S. Real Time Interactive Simulation 
  [Video Game Computer Science]
  DigiPen Institute of Technology

  - Make the world what it could be, not what it is.
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