INTRODUCTION:
After hundreds of hours of testing and agony deep in the bowels of the testing labs, the world's foremost RTW experts have determined:

SCOPE:
Set Unit_Use_Shaders to True, and make sure Unit Settings is not set to 'lowest'.

PROCEDURE:
1. In your preferences.txt, use Notepad to ensure this line:
UNIT_USE_SHADERS:FALSE
reads:
UNIT_USE_SHADERS:TRUE

2. From RTW main menu, choose "Options"
3. Choose "Video Settings"
4. Click the little box, "Show Advanced Options"
5. In "Unit Settings", move the setting off the LOWEST, and set it to:
5.a. LOWEST: Pointy Feet
5.b. LOW: Has feet, but straight calves
5.c. MEDIUM: Feet and good rounded calves
5.d. HIGH: Ditto, but further away from camera

Note 1: You can also check/uncheck "Unit Shader" checkbox from ESC-Video in game.
Note 2: You can also do steps 3-5 while playing a game.