TRACE node in Kismet needs descriptions/info

[Jonny T]

Can anyone tell me how to use the trace node in kismet - (EDIT: As there is no info on the UDN or elsewhere - awaiting a description)

I want to do a raytrace from an emitter (laser beam) positioned within the world and cast it out along the x axis by 1024units - then see if it hits anything, I will then use a DELAY node to fire the trace off again (every 0.1sec) to detect what it hits. I will then make the BEAM particle use the distance to determine it's length along the x axis.

Please help

Many thanks

[OmegaMinus1]

Start: Any Actor this will use the Location of the actor as the Start XYZ of Ray
End: Any Actor this will use the Location of the actor as the End XYZ of Ray
HitObject: The World or Actor Hit (*See Below)
Distance: The distance form the Ray Start to the World/Actor Hit Location
HitLoc: The XYZ of the World/Actor Hit Location

Not Obstructed: Output when ray hits nothing
Obstructed: Output when ray hits something

*NOTE: Trace only works on world actors that have collsion volume and actors like the players and movers.


Example 1: Using the actors World Postions

[shot]http://www.bitSlap.me/TracePost3.png[/shot]

[shot]http://www.bitSlap.me/TracePost2.png[/shot]

Example2: Setting the actors World Postions before cast

[shot]http://www.bitSlap.me/TracePost1.png[/shot]

Hope that helps!
Omega

[Jonny T]

Omega - MASSIVE thanks mate - I don't think i've ever had that much of a direct and helpful response, Thank you - your name shall be written forever in the credits of our game/mod

I'll post up a full tutorial on the gameplay mechanic that i'm prototyping here when i'm done, as a few people are currently wondering how to get a laser (beam) particle effect to hit objects that intersect the beam.

J

[Jonny T]

Oooh - BTW - do you know if you can set the 'End' position to an offset axis of the 'Start' object? i.e. 1024 units along the x axis (of the object)? Reason being that if the start object rotates or moves, I need the end to change position also (fixed to the objects x axis). Can this be done, or does there always need to be an 'End' object?

J

[ffejnosliw]

Attach the end object to the start object and it will move and rotate with the start object, effectively giving you exactly what you proposed.

[OmegaMinus1]

CoolCool no problem,

[shot]http://www.bitSlap.me/TracePost4.png[/shot]

[OmegaMinus1]

If you ever plan on rotateing the LaserActor then what ffejnosliw said is a much better approach to advoid a bunch of vector code.

[Jonny T]

Attach the end object to the start object and it will move and rotate with the start object, effectively giving you exactly what you proposed.

Haha - that's EXACTLY what I went for straight away - problem is - when I try attaching a 'Note' it throws up the old -

'Some object assignments failed because of cross-package references'

error - I did the classic - change my map name, but this seems to be a problem with attaching a note to another actor, as it does it with all actors when trying to attach a note.

any other ideas?

[OmegaMinus1]

I would attached a hidden static mesh actor same result.

[Jonny T]

I would attached a hidden static mesh actor same result.

Yeah - good call, I just want this as a prototype anyways - a not would be nicer for 'neatness' sake

[Jonny T]

This method of using an actor as the end point is really inconvenient when I'm trying to place multiple instances of a laser in the world, is there any way I could use the particle's target property/any other way of doing it? I tried making a Prefab out of the emitter and target object, but it causes the UDK to crash :P

[Jonny T]

[SOLVED]

WICKED - No additional objects needed just hook up the START AND END up to the SAME object and then type in an END OFFSET value - i.e. 1024

Doh!

[edx76]

*NOTE: Trace only works on world actors that have collsion volume and actors like the players and movers.

You mean it doen't work with a camera actor?