Sphere Primitive

Sphere produces a full sphere, or a hemisphere or other portion of a sphere. You can also "slice" a sphere about its vertical axis.

• Create panel > (Geometry) > Standard Primitives > Object Type rollout > Sphere button
• Standard menu: Create menu > Standard Primitives > Sphere
• Enhanced menu: Objects menu > Primitives > Sphere

Examples of spheres

Procedures

To create a sphere:

1. On the Create menu choose Standard Primitives Sphere.
2. In any viewport, drag to define a radius.

   As you drag, a sphere emerges with its center at the pivot point.

3. Release the mouse to set the radius and create the sphere.

To create a hemisphere:

You can reverse the order of the following steps, if you like.

1. Create a sphere of desired radius.
2. Type 0.5 in the Hemisphere field.

   The sphere is reduced to exactly the upper half, a hemisphere. If you use the spinner, the sphere changes in size.

Interface

Creation Method rollout

Edge

Draws a sphere from edge to edge. You can change the center location by moving the mouse.

Center

Draws a sphere from the center out.

Parameters rollout

The defaults produce a smooth sphere of 32 segments with the pivot point at its center.

Radius

Specifies the radius of the sphere.

Segments

Sets the number of polygonal divisions for the sphere.

Smooth

Blends the faces of the sphere, creating a smooth appearance in rendered views.

Hemisphere

Increasing values progressively will "cut off" the sphere, starting at the base, to create a partial sphere. Values range from 0.0 to 1.0. The default is 0.0, producing a full sphere. A setting of 0.5 produces a hemisphere, and 1.0 reduces the sphere to nothing. Default=0.0.

Chop and Squash toggle creation options for Hemisphere.

Chop

Reduces the number of vertices and faces in the sphere by "chopping" them out as the hemisphere is cut off. Default=on.

Squash

Maintains the number of vertices and faces in the original sphere, "squashing" the geometry into a smaller and smaller volume toward the top of the sphere.

Effects of Chop and Squash during hemisphere creation

Slice On

Uses the From and To angles to create a partial sphere. The effect is similar to lathing a semicircular shape fewer than 360 degrees.

Slice From

Sets the start angle.

Slice To

Sets the stop angle.

For both settings, positive values move the end of the slice counterclockwise; negative values move it clockwise. Either setting can be made first. When the ends meet, the whole sphere reappears.

Smoothing groups are assigned to sliced spheres as follows: The surface of the sphere is always assigned group 1; the bottom, when Smooth is on, gets group 2. Facing the pie-slice surfaces, the cut on the left gets group 3, and the cut on the right gets group 4.

Material IDs are assigned to sliced spheres as follows: The bottom is 1 (when Hemisphere is greater than 0.0), the surface is 2, and the slice surfaces are 3 and 4.

Base To Pivot

Moves a sphere upward along its local Z axis so the pivot point is at its base. When off, the pivot point is on the construction plane at the center of the sphere. Default=off.

Turning on Base To Pivot lets you place spheres so they rest on the construction plane, like pool balls on a table. It also lets you animate a hemisphere so it appears to grow out of the construction plane or sink into it.

Effect of using Base To Pivot setting

Generate Mapping Coords

Generates coordinates for applying mapped materials to the sphere. Default=on.

Real-World Map Size

Controls the scaling method used for texture mapped materials that are applied to the object. The scaling values are controlled by the Use Real-World Scale settings found in the applied material's Coordinates rollout. Default=off.