can neone xplain me collisions

how do collisions work.
do objects have to be physical for detecting collisions ?
a non physical object is able to detect a physical object touch or avatar collision but is not detecting land collsion and other non physical object collision and also scripting collision.
plz explain neone how this thing works, need it urgently ??

that i read already but nothing has been given for physical property to be set or not

The secret to solving your problem is to experiment with the various settings and learn from the experience ^^

Only physical movement can CAUSE collisions. Physical objects and avatars move with physical movement. However, any (non-phantom) object can be involved in a collision and can detect that collision. That means you cannot have a non-physical object collide with a non-physical object, but any other combination is possible. Attachments detect collisions with the avatar to which they are attached, not the attachment itself.