Inteface functions, get z coords.

[Anonymous]

Function from " Interface functions"

endInd = polyInfo.nCoords; 
			for (ind = 1; ind < endInd; ind++) { 
				begCoord.x = (*polyInfo.coords) [ind].x; 
				begCoord.y = (*polyInfo.coords) [ind].y; 
				begCoord.z = (polyInfo.zCoords != NULL) ? (*polyInfo.zCoords) [ind] : 0.0; 
 
				endCoord.x = (*polyInfo.coords) [ind + 1].x; 
				endCoord.y = (*polyInfo.coords) [ind + 1].y; 
				endCoord.z = (polyInfo.zCoords != NULL) ? (*polyInfo.zCoords) [ind + 1] : 0.0; 

I need to get z coords, but
begCoord.z = (polyInfo.zCoords != NULL) ? (*polyInfo.zCoords) [ind] : 0.0;
sets zCoords to 0. And if i use begCoord.z = (*polyInfo.zCoords) [ind] it freezes and returns no values at all.

Can anyone help in this ? I need to draw "box" in x,y,z and get all coords, at least furthest from beginning.