Justin Couch wrote:
>
>
> Ah, but this demonstrates my point. Are you using WakeUpOnCollisionEntry
> events for your terrain following? Using pick utils for your own custom
> collision detection is not the same thing. Using PickUtils is very
> different to using the behaviour system, which is supposed to be the way
> to do collision systems.
We do not use the WakeUpOnCollisionEntry behaviors stuff. But that is
because to do the collision we are doing we need to know information
about the geometry we are colliding with not because it's implemented
incorrectly. We need/want to do line segment testing. The problem is
that what most people think is simple collision turns out to need this
line segment type.
>> Is collision detection an easy problem? Usually no. Does Java3D make
>> it harder or easier? I'd say easier.
>
>
> Well, the first assumption by newcomers is that you use the classes
> named WakeUpOnCollisionEntry for collision detection. Surprise,
> surprise, we have to use something called picking to do collisions. Why
> can't I use the class that has the word "collision" in it's name? Seems
> very counter-intuitive. These programmers have to then understand how to
> create all the extra objects and potentially a big pile of vector math
> to get something useful (particularly n-body collisions. Terrain
> following is relatively simple by comparison). When the API states a
> capability it should just work rather than having to wander off to ask a
> pile of questions and get sent off to some seemingly unrelated topic
> area.
(Side note: Terrain collision may be relatively simple in THEORY but in
practice it is a different matter due to the optimizations you'll need
to make it fast and error free...)
You DO have to do a big pile of vector math to perform true polygonal
collisions. Especially if you want to do something with the collision
information!
As far as N-body collision, we do SOME of that using bounds and segments
(including basic kinematics, vector reflection, mass and inertia. etc.
But what is sounds like you want is a Physics engine, something you can
configure and just goes...There are several commercial systems available
(Havok, MathEngine) used in gaming and vis-sim.
That is definitely not in the scope of Java3D, and IMHO shouldn't be.
--
___________________________________________________________
Shawn Kendall Full Sail Real World Education
Course Director 3300 University BLVD
Real Time 3D for Gaming Winter Park FL 32792
[EMAIL PROTECTED] http://www.fullsail.com
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