Dropping a non-physical object.

Ok so I have a 75-prim object here, and I'm dropping it from a hight of whatever the ground height is + 35 meters. I can get the object up there easily, but when dropping it, I'm using a succession of 4 seperate movement scripts done in succession with timers. I didn't write the entire script so I'm not quite sure how it works. When testing though, it does not work at all terrains, and sometimes it doesn't even drop. Sometimes it drops half-way, sometimes it's dropped with like 7 meters left. Only in one sim has it worked all the way. I have no idea why it's doing this. Any ideas?

Here's the script that controlls the 4 movement scripts:

// Non-Physical Flying Vehicle
// A.K.A: How to exploit tricks in LSL to get your way
// 
// (your way being: up to 254 prims on a vehicle, in this case)
// Author: Jesrad Seraph
// Modify and redistribute freely, as long as your permit free modification and redistribution

integer hidden_face = 5;
 
float max_fwd = 2.0;        // max speed in m per quarter of a second
integer max_rot = 4;        // max turning speed in degrees per quarter of a second
float hover_height = 1;    // prefered minimum height above ground
   
float fwd_accel = 0.015625;    // forward/back acceleration  
float up_accel = 0.015625;    // vertical acceleration
    
float inertia = 0.75;        // movement slowdown rate
float moment = 0.5;        // turning slowdown rate

// internal stuff, don't modify 
vector velocity; 
vector veloff = <0.5, 0.5, 0.5>;
integer timeout; 
integer number = 100;
    
stop()  
{  
    llResetOtherScript("move");
    llResetOtherScript("move1");
    llResetOtherScript("move2");
    llResetOtherScript("move3");
    llSetColor(velocity + veloff, hidden_face);
    timeout = 0;
    //llSetTimerEvent(0.0);
    velocity = <0.0, 0.0, -0.5>;
    if (timeout == 0)
    {
        llMessageLinked(LINK_THIS, max_rot, "nonphy", (key)((string)max_fwd));
        llSetTimerEvent(0.05);
    }
    timeout = 12;
}

default
{
    state_entry()
    {
        stop();
    }

    on_rez(integer param) 
    {
        llResetScript();
    }
    
    timer()
    {
        if (--timeout == 0)
        {
            llResetOtherScript("move");
            llResetOtherScript("move1");
            llResetOtherScript("move2");
            llResetOtherScript("move3");
            llSetTimerEvent(0.0);
            return; 
        }
           
        if (velocity.z > 0.0) velocity.z = 0.0;
        velocity.z -= up_accel;
        if (velocity.z < -0.5 ) velocity.z = -0.5;
        if (llGetPos() * <0,0,1> < llGround(llGetPos()) + hover_height)
        {
            velocity.z = -0.25; 
            llMessageLinked(LINK_ALL_OTHERS, number, "", NULL_KEY);
            number++;
        }
        
        if (llVecDist(llGetPos(), llGround(llGetPos()) * <0,0,1>) < 11.0)
        {
            velocity.z = -0.05;
        }
        
        if (llVecDist(llGetPos(), llGround(llGetPos()) * <0,0,1>) < 0.05)
        {
            velocity.z = 0;
        }
        
        llSetColor(velocity + veloff, hidden_face);  
    } 
}  

And here's the code for one of the movement scripts (they are all the same, just numbered differently)

integer hidden_face = 5;

float max_vel;
vector veloff = <-0.5, -0.5, -0.5>;

default
{
    link_message(integer part, integer code, string msg, key id)
    {
        if (msg != "nonphy") return;
        max_vel = (float)((string)id);
        llSleep(0.05 * (integer)llGetSubString(llGetScriptName(), -1, -1));

        while(TRUE)
        {
            llSetPos(max_vel * (llGetColor(hidden_face) + veloff) + llGetPos());
            llSetPos(max_vel * (llGetColor(hidden_face) + veloff) + llGetPos());
            llSetPos(max_vel * (llGetColor(hidden_face) + veloff) + llGetPos());
            llSetPos(max_vel * (llGetColor(hidden_face) + veloff) + llGetPos());
            llSetPos(max_vel * (llGetColor(hidden_face) + veloff) + llGetPos());
        }
    }
}

in your controller script . . . where you call llGround (both times) you do it at 0,0,currentheight which might or might not be what you are looking for. Try removing the * <0,0,1> from those calls.

Just glanced at it but that's what I'd try first.

Is this an attempt to determine your altitude?

llVecDist(llGetPos(), llGround(llGetPos()) * <0,0,1>)

If so, it won't work (and is way more complicated than it needs to be, even if you did fix the errors in it). You probably want something like this:

vector loc = llGetPos();
float altitude = loc.z - llGround(ZERO_VECTOR);

Yeah none of those things worked
THe problem with your idea, gaius, is that I need the statement to be executed at the if statement itself, not before. As for the <0,0,1>, I use that to isolate the z vector.