Guided loft: Create a surface with bidirectional scaling

Description: 5 minutes; Lab exercise: 20 minutes

Normally, scaling is done in all directions within the profile plane and with an attachment point on the spine as the center.  With the Bidirectional Scaling option, you can specify two scaling functions that have their influence in two specific directions orthogonal to one another.

When Bidirectional Scaling is selected, two vectors are shown at the start and end of the spine in the "up" direction.  In the Guided Loft dialog, the vectors are defined in Start Up Dir and End Up Dir.  The two vectors are interpolated along the spine and can be influenced by using the Orientation Options.

Modify these "up" vectors by specifying an option for Up Scale and Side Scale.  The Side Scale function has an orthogonal influence on the Up Scale option.

Lab exercise

  1. Load the variationoptionsscaling.pkg file.
  2. Click Surfacing .
  3. Click Guided Loft in the Create Face section.
  4. Select the straight line as the Spine.
  5. Select the box as the Profile Edges.
  6. Expand the Variation Options section.
  7. Click Bidirectional Scaling.
  8. Select Parabolic from the Up Scale drop down menu.
  9. Type 2 in the Mid field.
  10. Select Parabolic from the Side Scale drop down menu.
  11. Type 2 in the Mid field.
  12. Click Preview.

  1. Now, change the Up Scale and the Side Scale to Three Values.
  2. Type 2 for the Start Weight for both and leave the rest of the values as they are.
  3. Click Preview again.

  1. Continue changing the Up Scale and Side Scale options and typing in new values to practice with Bidirectional Scaling.
  2. Click to finalize your model.

Result of 2D Curve selected for both Up Scale and Side Scale options