Spatial Transformation
A portal stitches the existent space with a transformed space. It can have translation transformation, rotating transformation, scale transformation, and mirror transformation.
This mod's teleportation is eye-based. The teleportation applies the transformation to the player's eye position. This makes the teleportation visually seamless. However, this doesn't guarantee that the player will be in empty space after teleporting.
After crossing a portal with rotation transformation, the player's camera may be tilted. Then the camera rotation will smoothly turn into a valid state.
The portal has a property teleportationChangesScale. If it's false, the entities that go through the portal will have the scale remain unchanged.
If it's true and Pehkui mod is installed, teleportation will change the entity's scale.
If Pehkui mod is missing or you are using the Forge version, teleportation won't change the entity scale.
Mirrors do not allow teleportation.