Java3D World coordinate system vs. Object coordinate system
Joined: Jun 25, 2002
Hi, Im new to Java3D but have a fair to good amount of 3D application development experience. I am trying to write a swing application that has an object centered around the origin. I want to be able to rotate this object around, but it seems to me that when I perform the rotations using the functions transform3D_object.rotX(radians); etc, it rotates the object around the WORLD coordinate system. I am trying to figure out how to get the rotations to apply to the OBJECT's coordinate system. That is to say, the object has an implicit x,y, and z axis of its own. I want the rotations to be performed about the object's coordinate system. Therefore, say if the object is rotated about it x axis, the object's y axis will rotate around, so if you then do a rotation about the object's y axis, that rotation would not be the same as rotating the object around the world's y axis. I see in a Java3D book I have that you can use quaternions to rotate an object about an arbitrary axis. I guess what i really want to know is that is it true that a) objects being rotated using the rotX function ALWAYS are rotated around the world coordinate axis, regardless of orientation of the object's coordinate system. and b) if so, what is the method for doing rotations about an object's coordinate system if a) is true. Thanks for the help, I much appreciate it.
Joined: Jan 07, 2002
Hi "Greg B", welcome to JavaRanch. Sorry I can't answer your specific question as I don't know much about the Java3D API, although I have the Manning book and plan to go over it at some point. In the meantime, please change your name to comply with the naming policy to which you agreed when you registered here. You need more than a single letter in your last name.
For your publicly displayed name, use a first name, a space, and a last name.