Ray cast help

[ItHadToComeToThis]

I need some help in detecting a prim with a script inside using a raycast. I am a tad confused as to why this isnt working

rCast=llCastRay(llGetPos(),llGetPos()+<2.5,0.0,0.0>*llGetCameraRot(),[RC_REJECT_TYPES,RC_REJECT_LAND,RC_DETECT_PHANTOM,TRUE,RC_DATA_FLAGS,RC_GET_ROOT_KEY,RC_MAX_HITS,1]);

The only thing i want it to reject is hitting land. Any other kind of object i need it to detect. I have no other reject flags except land. Can anyone point out what i missed here.

 

[Wulfie Reanimator]

2 hours ago, ItHadToComeToThis said:

I am a tad confused as to why this isnt working

Yeah, why isn't it?

Are you getting errors? Are you not hitting objects? What's happening and how is it different from what should be happening?

[Qie Niangao]

Not sure why you're not getting some result, but if you're doing what I think you're doing, you may eventually want to cast from llGetCameraPos() in the direction of llRot2Fwd() of llGetCameraRot(). I have a sample in a box somewhere around http://maps.secondlife.com/secondlife/Bay City - Dennis/133/230/26 if it helps to take a look.

[ItHadToComeToThis]

2 hours ago, Wulfie Reanimator said:

Yeah, why isn't it?

Are you getting errors? Are you not hitting objects? What's happening and how is it different from what should be happening?

 

50 minutes ago, Qie Niangao said:

Not sure why you're not getting some result, but if you're doing what I think you're doing, you may eventually want to cast from llGetCameraPos() in the direction of llRot2Fwd() of llGetCameraRot(). I have a sample in a box somewhere around http://maps.secondlife.com/secondlife/Bay City - Dennis/133/230/26 if it helps to take a look.

Well, as it turns out I discovered it was working there was just something wrong with my ray cast which might well be what Qie is describing above. The object it wasn't hitting would return a value but only when I aimed at the top left corner of the object. I am going to play around with it later on when I log back into SL and try what Qie has suggested.

I had a box rezzed in the air in front of me and I can aim at most of it all day long and it returns no results, but aim at the top left and I get a hit. So, I would use llGetCameraPos()+<2.0,0.0,0.0>*llRot2Fwd(llGetCameraRot())?

Further question on topic but not on this part of it. Is it possible to curve a single ray so it sweeps an area or would that just involve me casting multiple rays across those directions?

Edited May 12, 2020 by ItHadToComeToThis

[Fenix Eldritch]

It may be helpful to have a debug routine where you rez a marker prim at the coordinates the ray impacts, and perhaps also at the calculated endpoint you fed into the llCastRay function.

As for sweeping a single ray, that is not possible. The llCastRay function will fire a single ray between the start and end positions and it is practically instantaneous. You would need to set up and fire multiple rays in a sweeping pattern to cover any area other than a straight line.

[Wulfie Reanimator]

3 hours ago, Qie Niangao said:

in the direction of llRot2Fwd() of llGetCameraRot()

2 hours ago, ItHadToComeToThis said:

So, I would use llGetCameraPos()+<2.0,0.0,0.0>*llRot2Fwd(llGetCameraRot())?

• "llRot2Fwd(rotation)" returns the local X axis of that rotation.
• It can be simplified to "<1,0,0> * rotation"
• And since the ray needs to be 2 meters long instead of 1 meter, it can be changed to "<2,0,0> * rotation"

This is pointed out even on the wiki page of the function.

[ItHadToComeToThis]

11 hours ago, Wulfie Reanimator said:

• "llRot2Fwd(rotation)" returns the local X axis of that rotation.
• It can be simplified to "<1,0,0> * rotation"
• And since the ray needs to be 2 meters long instead of 1 meter, it can be changed to "<2,0,0> * rotation"

This is pointed out even on the wiki page of the function.

Okay so. I have fixed it and now i'm facing another issue. I need the ray to not detect myself while i'm running and firing it. I have tried starting the ray from all kinds of different places up to 1m in front of me and it still detects me if i am running forward. Annoyingly i could do with it firing from the camera position in mouse look for up close combat so 1m away isn't ideal.

I have thought about putting in a filter that tells it to ignore any casts that are not the caster but is there a way to get the ray to just flat out ignore the caster in the  same way the RC_REJECT flags work?. I cant see anything on the wiki

[Wulfie Reanimator]

30 minutes ago, ItHadToComeToThis said:

Okay so. I have fixed it and now i'm facing another issue. I need the ray to not detect myself while i'm running and firing it. I have tried starting the ray from all kinds of different places up to 1m in front of me and it still detects me if i am running forward. Annoyingly i could do with it firing from the camera position in mouse look for up close combat so 1m away isn't ideal.

I have thought about putting in a filter that tells it to ignore any casts that are not the caster but is there a way to get the ray to just flat out ignore the caster in the  same way the RC_REJECT flags work?. I cant see anything on the wiki

Welcome to Classic SL Combat Problems #9752.

No, you can't outright reject the caster/owner. The typical solution is to start from some distance in front of the avatar, possibly while accounting for velocity.

Another solution is to change RC_MAX_HITS to 2 and explicitly ignore the first hit if it's the owner.

Edited May 13, 2020 by Wulfie Reanimator

[ItHadToComeToThis]

You would have thought they might have given us an RC_REJECT_SELF or RC_REJECT_OWNER.....okay il figure a work around. Thanks for the response

[Fenix Eldritch]

You mentioned earlier that you want to do a sweeping pattern, which would require multiple rays... assuming that's still the case, are you updating the start position for each new ray? If not, that might be why you keep hitting yourself as you move forward. The origin might be correctly positioned ahead of your avatar for the first ray, but by the time you cast the next one, your avatar may have moved into range.

Are you casting all the rays in the sweep at once and then processing them afterwards, or are you processing each one as they are cast? That could be the difference.

Edited May 13, 2020 by Fenix Eldritch