Scale object in 1 direction

Hey! I’m trying to make a lava floor. To do this, I’m trying to place the lava in a corner, and scale the object along the entire floor. However, when I scale it enlarges the object from both sides. Does anyone know how can I get an object to either only enlarge on 1 side, or snap to fill a room?

The easiest way is to change the pivot point in the editor:

Another way is in your 3D modelling software to change the origin point of your mesh object to the corner of the mesh, so that scaling does not scale from the center but from the corner.

Oh that worked, thanks!! It looks like all I need to do is set the pivot location to the end of the actor, and it will go ahead and extend just the 1 direction (mostly)