I'm guessing this is an incredibly basic question but I'm hitting a total brick wall with it.... :brokencomputer:

I'm trying to remove collision from the leaf planes attached to a tree mesh (well, a couple of trees actually), but whatever I try it doesn't work.

Specifically, I right click the leaf plane, choose "Flags" and set this to "None", choose Accept and then save the mesh but nothing happens .... that is, collision isn't removed, so the leaves are still effectively a solid wall.

What exactly am I doing wrong, or does this function just not work (using NifSkope)?

Anyway thanks for any help.

Assuming you have a level 0 node reserved for game engine scaling, try this:
NiNode0
--NiNode1 (all your tree mesh)

- right click NiNode1, block\insert\NiStringExtraData NCO
- click the tree trunk, it should select the trunk trishape inside NiNode1 subfolders
- right click the selected trunk trishape, block\copy branch
- right click NiNode0, Node\Attach node\RootCollisionNode
- right click the RootCollisionNode just created, block\paste branch
in the RootCollisionNode just pasted, delete everything except NiTrishapeData