I believe this (great) book has an algorithm that works for concave shapes:
http://cs.smith.edu/~orourke/books/compgeom.html
I'm sure one of the Graphics Gems book probably has something too... I
believe the code to the books is on the Internet.
Best of luck,
Daniel Selman
R K Shyam Prakash wro
Hello java3D people.
I have been discovering this java3D mature API.
I like it.
Nevertheless I have been strugling for over a week (shame on me) to
add in front of my 'Camera' of little shape/avatar that will pretent to be the guy walking along
the 3D Scene.
I Tried a few thing (thanks Rolf
i have a problem when navigating in my 3d environment:
After moving backwards for a certain amount, i am unable to move anymore its as if i have reached a boundary, or a point of no return and it can't even be refreshed, i have to rerun everytime that happens
if that is familiar to anyone pleas
Bolaji,
I am not a j3D expert but I used to have the same problem.
the thing is that you navigate because of a Behavior...
And this Behavior classe is 'Active' only in a space region by definition.
You tell this with yourBahavior.setBounds(...) method.
You must therefore enlarge your bouding
- Original Message -
From: "R K Shyam Prakash" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, March 15, 2004 6:49 AM
Subject: [JAVA3D] Vlume Calculation
> Hi,
> I have a 3d model represented by a set of triangles. Assuming
> that the model does not have any holes in it,
Hi, I think someone may be able to help me, I get the following error
while trying to remove a branchgroup from my scene, the branchgroup
contains a collision detector that holds a copy of the transformgroup,
im sure that this is the problem, just don't know how to fix it? If you
need any more info
What i really know about java.lang.NullPointerException is that you are putting a
DOT on an object(executor) of a method that is null. In this case the object or the
executor is null at the time it is called. send some piece of code to clarify this.
Isaac Kwame
The problem is that in that case, the ones who's putting the dot are the sun's
developers. The NPE occurs in a place where it should never happen, i.e. an internal
java3d class that you can never deal with in your code:
javax.media.j3d.TransformGroupRetained. Clearly a bug.
However, the Sun guy
Hi,
I need a version of Alpha for use with Sun's Interpolators that fires,
when it is paused, finishes and reaches 1.0
Does anybody have anything similar?
Essentially, I need to know when the interpolator has finished. Is there
another way of knowing this?
At the moment, I have a low priority thre
I'm not sure what your problem is. You have to add your avatars Shape3D to
your ViewPlatforms TransformGroup using an additional TransformGroup which
positions this Shape3D in some distance to your "camera" (e.g. one meter
away).
On Mon, 15 Mar 2004 11:20:40 +0100, Thierry Milard (free)
<[EMAIL PRO
Paul,
Write your own Alpha implementation class. I have a couple of examples
in my book. Code here:
http://www.manning.com/catalog/view.php?book=selman&item=source.html
Look at the customalphatest examples.
Sincerely,
Daniel Selman
Paul Brown wrote:
Hi,
I need a version of Alpha for use with S
Hi Daniel,
I have your book and source code - they have been an inspiration to me.
If I understand you correctly though, and after looking at your
FileAlpha class, your suggestion of writing my own class which extends
Alpha would mean either:
1) repeating the time incrementing calculation, because
Another thing to check: I see where you set the BackClip, but not the
FrontClip. Make sure you aren't clipping your avatar out because it's
too close!
Michael Pfeiffer wrote:
I'm not sure what your problem is. You have to add your avatars
Shape3D to
your ViewPlatforms TransformGroup using an add
Actually, maybe not, because the interpolators must call the Alpha
value() method on a frequent basis. My own Alpha class could simply
intercept those calls, test the value on its way back and fire events
accordingly.
A fiddle but it might just work.
Thanks,
-Paul
Original Message ---
Ben,
It is likely that you are detaching the BG in a user thread. If this is
true, you will need to synchronize the detach operation with the j3d's
update threads which is rather complicated. This is a known bug in j3d :
BugId 4340607 - Node and NodeComponent's set* methods not synchronized
You are absolubly right.
I mastked in adding only one transform group.
In fact I had to add another Transform group wich puts the shape ahead of the camera.
Thanks.
---Original Message---
From: Discussion list for Java 3D API
Date: lundi 15 mars 2004 18:19:04
To: [EMAIL PROTEC
thanks for your help thierry...
another thing: i've created a object which is meant to represent the floor, using geometryinfo. However when added to the scene graph, i can only see this floor object from underneath i.e. move up and am effectively looking down on the "floor" i can only see the back
Yes. One way of doing this would be to derive your own class from the
J3D Alpha class and override the value() method. You can then call
super.value() to get the value as calculated by J3D and react as you need.
Dan
Paul Brown wrote:
Actually, maybe not, because the interpolators must call the Alp
I get the following trace when I try to add an OrderedGroup as
an element of a subgraph under a SharedGroup - is it permissible
at all to do this ? Couldn't get anything to the contrary from the
API docs !
java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.ArrayList.get(ArrayList.ja
The Java 3D Frequently Asked Questions list for Monday March 15 2004
This is a posting of topics covered in the Java 3D FAQ. The answers
to these questions are kept at:
http://www.j3d.org/faq
Please consult this list and the web site before asking questions on the
mailing list.
If ther
I'm using the following Transform3D
m_00 = -1, m_11 = m_22 = m_33 = 1, and zero for all other elements,
on a TransformGroup to effect a reflection of the scenegraph about
the yz-plane. And when I do that, the geometry gets transformed correctly
but the diffuse and specular lightings get clobbered
Vaidya,
Based on the trace, I believe you've hit a known j3d bug. As alway,
a test program will
be very helpful to us.
BugId : 4900656 - IndexOutOfBoundsException while create scene with
OrderedGroup.
thanks,
- Chien Yang
Java 3D, Sun Microsystems Inc.
N. Vaidya wrote:
I get the followin
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