Hello T.
It seems the elev message is not working properly with spat.oper and spat.viewer. Sending a message such as “source 1 elev 30” for example to spat.oper or spat.viewer will place the source’s elevation at -81. The correct values seems to be scaled between something like [-1.5, 1.5].
Please confirm the behavior.
System OS X
Spat version: 4.7.6
Max version: 6.1.9