Reform

reform maneuver allows unit to change facing direction while it stands still (slowly moves in DO). 

Reform performed at speed which depends on unit’s Movement. The speed simulates that unit’s formation is cumbersome, and it is hard for numerous models to change facing direction instantly. This is not the case for unit which consists of single model though.

Reform in DO

It is possbile to make manual reform while unit stands or automatically when unit is on the move. During movement unit slows down and waits while its models change facing direction and take new formation spots.

Unit uses auto-Reform when required turn angle exceeds 90 degrees (pls, see video). Otherwise unit uses Wheel maneuver.

Pls. see diagram which illustartes Wheel and Reform zones.
The 90 degrees turn angle is measured from 1st unit rank. 
If player clicks in yellow zone (0 - 180 degrees)  - unit wheels.
If player clicks in green zone (181 - 359 degrees) - unit reforms

Unit also uses Reform when it has to change formation.

Unit can auto-reform only 90 or 180 degrees from its current position. If unit still does not face required movement vector it will use wheel maneuver. Same rules are used in 4th and 5th editions of TT rules (pls, see below)

Wheel and Reform zones

Reform maneuver speed affected by unit:

• Movement characteristic
• Initiative characteristic 
• models number (since one model size unit does not spend time for its models to change spots in formation)
• formation type (not 100% sure)

Reform formula

is unknown at the moment