Part Modeling > Base Features > Blends > Rotational Blends > About Rotational Blends
  
About Rotational Blends
A rotational blend is created using sections that are rotated about an axis of revolution. If the first section you sketch or select contains an axis of revolution or a centerline, it will be automatically selected as the axis of revolution. If the first sketch does not contain an axis of revolution or centerline, you can select geometry as the axis of revolution.
You define the section orientation in relation to other sections. All the sections must lie in planes that intersect at the same axis of rotation. For sketched sections, you can define the sketch plane for the sections by using an offset angle from another section in the blend, or by selecting a reference.
If you define a rotational blend as closed, Creo uses the first section as the last section and creates a closed feature. There is no need to sketch the last section.