The Anchored property determines whether the part will be immovable by physics. When enabled, a part will never change position due to gravity, other parts collisions, overlapping other parts, or any other physics-related causes. A part that is not anchored is called unanchored. As a result, two anchored parts will never fire the /BasePart/Touched event on each other. An anchored part may still be moved by changing its /BasePart/CFrame or /BasePart/Position, and it still may have a nonzero /BasePart/Velocity and /BasePart/RotVelocity. Finally, if an unanchored part is joined with an anchored part through an object like a /Weld, it too will act anchored. If such a joint breaks the part may be affected by physics again.

It’s a good idea to anchor parts that are part of your game’s environment (and therefore shouldn’t move). In fact, if you don’t have a good reason to keep a part unanchored, you should anchor it. Unanchored parts can cause performance issues if there are many. In Roblox Studio, you can anchor/unanchor an entire model using the Anchor tool. Be sure to keep static environment models anchored, like in-world buttons, signs, and trees.

Network ownership cannot be set on anchored parts. If a part’s anchored status changes on the server, the network ownership of that part will be affected.