Rezzed object not on level ground

I made an object with several prims. I specifically took care that the base-prims of the object are on level ground. But when I rezz the total object in-world, it rezzes above ground.

The cause is a cutt offed cilinder, which is part of the object. What can I do to make the total linked object (including the cilinder) rezz on level ground instead of above ground?

EDIT: code was not tested and is broken. See post #5. Sorry.

SL uses the centroid of the bounding box of a set of linked prims to determine its placement point relative to the world. The "bounding box" is the smallest rectangle - oriented along the XYZ axes - that you could fit around the linkset. I do not know whether the bounding box calculation respects cut prims; my guess is that it does not.

If your object always rezes a certain distance above the ground or floor, you could add a script like

float displacement = 0.5; // how high the object rezes above ground (m)
   
   on_rez() {
     vector v = <0, 0, displacement>;
     llSetPos(llGetPos() - v);
   }

in the root prim.

If it doesn't always rez at the same height, then this won't work. I've seen instances where rezzing a new cube fails to "hit" the surface, so there may also be generic problems in rezzing.

Good luck.

A script such as the previous poster mentioned is the only automatic solution.

Any cut prims that are on the lower sueface of a linkset are treated as if they were NOT cut, for purposes of rezzing placement. So if you had a half-cylander with the cut face toward the ground, the linkset will rez above the ground by a distance equal to the z-axis radius of that cylander.

Okay, makes sense. Thanks to you both for the explanation. Will try the script in order to maintain the design quality of my object. Hehe. Thanks a lot.

EDIT:

Hmm, I'm getting a syntax error on (2, 0) That is on_rez. Should the script be part of a larger script with default state etcetera?

that's useful, thanks! i tend to often use cut prims for chair legs and have this problem.

Great Ed, that works perfectly. Thanks to you all for replying!!!

Note. The script in post 5 ONLY works if you are rezzing the object on the terrain ground level! If you rez it inside a building or in a skybox, it still rezzes relative to the ground!

The following script works in buildings and skyboxes as well.

// adjust this height 
float adjustHeight = -0.5; // how much the position should be adjusted when the object is rezzed. (m) -

default 
{ 
   on_rez(integer x) { 
      vector v = llGetPos (); 
      v.z = v.z + adjustHeight; 
      llSetPos(v); 
      } 
} 

Ooooowww Ceera. I thought this thread was to an end. And indeed the scripts above only work on land level. Your script will be a big, big help for everyone who wants their structures to rez right in all occasions. I just don't know why I missed your post though. Saw it again through a link in another topic. Anyway, thanks a lot!

In all fairness, all I did was slightly tweak the script that ed44 posted. He did most of the work in developing his version. But I'm glad it's useful.