I cant get it to work still:

I set up the locator and then added the expression but it's still only doing it in the viewport. the expression I have added is:

print("Doing LOD \n");
doLod;

I replaced the part of yours that just printed out "test". But i cant get it to pick it up in the batch render. What is the command that you are using to render from the command prompt? cause i have tried render -f filename etc and it says that I am specifying more than one file name:

render -cam cam E:\maya work\spiderHme\scenes\finalSpiderRigging\lodTest.m b -s 1 -e 19

arghhh this is so frustrating!

thanks for your help babyduck you're a star

Alan