Reference Topics > Example: Create a guided loft with unidirectional scaling
  
Example: Create a guided loft with unidirectional scaling
When using birails to create a guided loft surface, use Unidirectional to scale the profiles in two specific directions.
Isotropic (default) - Scale the profile in all directions within the profile plane with respect to the spine.
Unidirectional - Scale the profile in a direction determined by the distance between spine positions and corresponding birail positions. Or, scale the profile only in the direction given by two points where the profile plane intersects the birails.
Example using one birail
Spine (orange), profile (blue), birail (white)
Using the Isotropic option, the profile is scaled in all directions with respect to the spine.
Using the Unidirectional option, the profile is scaled in a direction determined by the distance between spine positions and corresponding birail positions.
Example using two birails
Spine (orange), profile (blue), and two birails (green)
Using the Isotropic option, the profile is scaled in all directions with respect to the spine.
Using the Unidirectional option, the profile is scaled in a direction determined by the two points where the profile plane intersects the birails.