Spline Guide Tool

Generally, the Spline Guide tool (Modify > Spline Guide) performs interactive deforming operations based on a guide curve. Clicking in the window creates the initial guide curve and center axis. Initially, the guide curve will be aligned along the longest distance of the selected geometry, extending from its minimum to maximum point. The center axis is centerd within the geometry.

Initially, the guide curve points have no effect on the geometry - like bones in their rest position. However, moving the points will vary the strength of the effect. Moving the center axis will change the influence of all the points on the curve.

What effect is applied is determined by the Operation setting on the numeric panel.

The Scale operation scales the geometry in the plane perpendicular to the axis around the center axis. Moving the guide points closer to the center shrinks the geometry, moving them farther away as it expands it.

The Stretch operation scales the model in the plane perpendicular to the axis around the center like the Scale operation, but uses different amounts of scaling in the plane (call it X-Y) depending on the X and Y distance of the guide points from their initial positions. Thus, the geometry can be expanded in one direction and reduced or left unchanged in the other.

The Twist operation rotates the geometry around the center axis. The Twist Angle parameter acts as an angle scaling factor.

The Bend operation bends the model to conform to the curve.

The Weight Map operation works a little differently than the other operations in that it doesn’t deform the geometry, but affects the selected Weight Map instead. Essentially, it sets the values based on the reshaped curve. Move them closer to the center axis for negative weights, farther for positive.

If you activate Make Curve, a curve polygon will be created from the guide curve when you deselect the tool. Use this to save the guide curve shape. This curve can be placed in a background layer and loaded into the guide curve by clicking Get Background Curve.

Click Keep Edit to accept the current changes without resetting the curve. This is useful if you want a certain curve to be applied in subsequent operations.

Changing the Curve Points value will resample the curve into more segments. Note that resampling the curve can change its shape, particularly if the number is incremented gradually, as is the case with the mini-slider. If you want a more refined curve that accurately matches the one you have drawn, enter the new number directly into the field to avoid the intermediate curves.