Hendoor64

My goal is to create a potion effect which allows the player to no-clip through some blocks but not others. How would I go about this? The potion effect itself and its application are taken care of. Thanks in advance.

I am trying to make a cloak item, a chest-slot piece of armor. It seems simplest to make the cloak look like an elytra and change the texture rather than making my own armor model, since I'm happy with how the elytra looks already. The cloak class currently extends ArmorItem. Thanks in advance for your help.