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Superellipsoid

A shape that morphs continuously from cube to ellipsoid to concave star through two exponents.

Superellipsoid morphs continuously between a cube, an ellipsoid and a concave star through two exponents. It is the quickest way to a rounded cube driven by one parameter.


Geometry

Follows Barr's parametric definition. The topology is the same ring grid as Sphere (single vertex at each pole), while the size is set per axis with Width, Depth and Height.

Roundness 1 (ε1) is the exponent of the vertical profile; Roundness 2 (ε2) is the exponent of the horizontal section.

RoundnessResult
0.01close to a cube
0.3 – 0.5rounded cube
1ellipsoid (sphere)
2octahedron-like
3 – 4concave star

The pivot is at the bottom, so a shape of height h occupies y=0 to y=h.


Parameters

LabelScript keyDefaultRangeDescription
Widthw10.01 ~ 1000Size along local X, in meters
Depthd10.01 ~ 1000Size along local Z, in meters
Heighth1-1000 ~ 1000Size along local Y, in meters
Roundness 1e110.01 ~ 4Vertical profile exponent (ε1)
Roundness 2e210.01 ~ 4Horizontal section exponent (ε2)
Segmentsseg243 ~ 128Divisions around the shape
Ringsrings122 ~ 128Bands along the height

The two exponents are independent. Lowering only ε1 approaches a flat-topped cylinder; lowering only ε2 gives a column with a square section.


How to create

  1. Drag in empty space to set the footprint (Width × Depth).

  2. Click to confirm, then move the mouse up to set the Height.

  3. Click again to finish, then dial in the exponents in the Inspector.


Scene view editing

The X, Z and Y handles drive Width, Depth and Height. Roundness is slider-only — drag it and watch the form change live.


Tips

For a rounded cube, Superellipsoid with Roundness 0.3–0.5 beats Box + Bevel — one parameter controls the fillet.

Above Roundness 2 the surface goes concave and polygons crowd together; raise Segments and Rings to keep the form readable.


Script

In a script this shape is written as superellipsoid.

superellipsoid "RoundedCube" w=1 d=1 h=1 e1=0.4 e2=0.4 @0,0,0
superellipsoid "Star" w=1 d=1 h=1 e1=3 e2=3 seg=48 rings=24 @2,0,0

See also — Shape Type List · Creating Shapes and Modes · Scene Script Syntax

Superellipsoid | UModeler X Manual