Here are a couple of rules from Thurs nights game.
Battlefield Debris: The Basics 40k6 pg 104
Unless otherwise noted, battlefield debris is difficult terrain, though elements of other types of terrain may also apply
Context: Avatar assaulted Purifier combat squad had to hurdle the Aegis Defense Line (ADL). Since Avatar is a Monstrous Creature he wasn't affected by difficult terrain. This rule is mentioned because it reminded me that ADLs trigger difficult terrain checks.
Shadowcl4w asked about the Avatar rolling 3D6 for charge through Difficult Terrain with it having Move Through Cover. This was covered in yesterdays Rules of the Game post. Here it is for those wanting that instant gratification.
Move Through Cover 40k6 pg 40
The Move Through Cover special rule has no effect on charge range rolls or Impact tests (see page 93).
Shawn wanted to confirm that since Avatar was a Monstrous Creature and
would roll 3D6 when moving through difficult terrain. Also wanted to
see if it affected charging as well. It does not.
Shadowcl4w brought an excellent point. Something didn't even consider regarding Monstrous Creatures and Charging through difficult terrain.
Charging Through Difficult Terrain 40k6 pg 22
However, to represent the uneven pace of a charge, the unit rolls 3D6, rather than 2D6, and use the two lowest as its charge result.
Context: Avatar should've rolled 3D6 and used lowest two instead of rolling 2D6 believing Move Through Cover affects random charge distance. It does not. Monstrous Creatures still roll 3D6 and use lowest two. Something to remember for next time. Thanks, Shadowcl4w!
Consolidation 40k6 pg 27
Units making a Consolidation move are not slowed by difficult terrain but do trigger Dangerous Terrain tests where appropriate.
Context: Eldrad and friends made a consolidation roll after taking a combat squad of Purifiers. Even though the squad was split by an ADL they did not have to make a difficult terrain test.