SIM

Not quite sure what you're asking. The in-built simulator works fine, although some may prefer those from scripts.

There are several combat simulators for the game, from which some developed by the players themselves are included in the game:

TACS: https://raw.githubusercontent.com/KRS-L/cncscripts.com/master/TACS.user.js
TABS: https://github.com/netquik/CnCTA-SoO-SCRIPT-PACK/blob/master/TA_Tiberium_Alliances_Battle_Simulator_V2.user.js

And there are also script packages that include them, although I'm not completely sure that all scripts work.
https://chrome.google.com/webstore/detail/center-driven-cnc-ta-basi/glicbealjcpdfcnkjeeememcglfoafbo
https://chrome.google.com/webstore/detail/cncta-soo-script-pack/mhohhaneodmbojhibocihibkiiafigkl

Have you looked in the forums?