Is a collision able to read on only one side fo a prim?

I am in the process of my very first scripting project. I have scripted an item with the help of some other open source scripts to read a collision and then give a blue dialog box with a message. Is there a way I can make the collision readable on only one side of the prim...for isntance..when entering through the doorway but not exiting it.

Instead, perhaps llDetectedVel() of the colliding avatar would help?

no, but you might be able to guess by determining the direction two objects ran in to each other from. combine what you collided with's velocity with your objects velocity and that might give you a pretty good guess.

Hmm I have no clue what that is *laughs* I am literally bran dnew to scripting.

It means you can request the direction which the coliding object is going. Combined with the movement of your own object (if any), you could then sort out from which side the collision came.

I created saloon type doors using two invisible phantom prims to detect colission on either side of the door (since they should swing in a different direction depending on if you're entering or exiting the saloon). I guess you could do the same here..
.___
|..|..|
|..|..|
|..|..|
|..|..|
|..|..|
|..|..|
|_|_|

If the lefthand prim is colided with first, hand out a notecard. If the righthand prim is colided with first, ignore colissions in the left hand prim till the colissions have ended...
I agree it's not ideal and a bit more work but I think it'll work all the same.

Lyn