Hi Have you tried the wakupOnCollisionEntry() and wakupOnCollisionExit() in the new j3d 1.2 alpha release (early access). They seem to behave quite differently as compare with the 1.1, the previous version. My codes which works in version 1.1, seems to be not working properly simply by using the 1.2 alpha release version. When I attached a collision detection behavior to a scene graph, the CPU cycle remained very low (in face, I don't think the CPU is doing any collision detection work at all). I know the 1.2 alpha release is said to fix up the free running thread of collision detection behaviour as in version 1.1. Anyone has similar problems? Thanks Regards, Sunny Leung =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff JAVA3D-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".