I'm wondering if there isn't a better way to position a newly created model on terrain. I am currently using this method, which doesn't always seem to work correctly even when the models origins are in the right place.

temp.z -= 10000;
my.z -=c_trace(my.pos,temp,use_polygon|ignore_me|ignore_passable|ignore_passents);

Maybe temporary physics until it hits the terrain? Just a weak idea.

I had the weirdest problem using the c_trace function for an elevation radar in that only every other trace gave a valid result (hit) and every other gave no result (null). It was very predictable. I never solved or figured out the underlaying cause but instead used a workaround by always doing two traces in a row and only using the one with a result. I did that by doing something like this:

c_trace();
if(result)
{
// do ent_create or whatever
}
else
{
c_trace(); // again
// then do whatever ...
}


I think it might be a bug in c_trace but I never filed a bug rep so I can't say for sure.

Hope this helps to solve your troubles too,
cheers,
tindust

It seems like there should be some way to identify the z value of the terrain surface at any particular coordinate.

like

z = ent_terrain.surface;

Wouldn't that be nice?

You can use target for that. The target vector is set to the world position of the point where your trace hits the surface. Its z is it.

Oh, if you meant the z of a specific terrain vertex that could be done with the vec_for_vertex but one would have to know the vertex number then. (I suppose that number could also be found with a c_trace ...).

This would be useless for the kind of terrain Jazzdude is talking about...it's poly-optimized and has huge spaces between the vertices

Sure, so what's the solution then ... ?

Maybe "use_box" instead of "use_polygon" helps...?

Well, I think we are talking about two different things here. 1/ If you want to find the coordinates of a vertex, well, they are far apart no matter what method one applies to find them. 2/ Finding a point of a trace hit I suppose will be the point interpolated inbetween vertices of the polygonized terrain if that is chosen for the trace. I have a hard time to see how a trace hit on the bounding box of the terrain would be more accurate. Maybe i misunderstand. Could you elaborate a bit ...