Constructing a Circle from a Sphere

You can construct a circle from a sphere at a specified diameter of the sphere, or you can construct it at a given height from the sphere centroid.

Valid input feature type

Sphere

Valid construct type

Diameter or Height

Available reference point (REF_POINT) options:

• SPHERE_CENTROID

Available reference vector (REF_VECTOR) options:

• SPHERE_VECTOR

• WORKPLANE

• ZPLUS

• XPLUS

• YPLUS

• ZMINUS

• XMINUS

• YMINUS

Construct type input value overview

When you use a Diameter construct type, the input value is the diameter of the resultant sphere circle.

PC-DMIS uses the input value as the diameter of the resolved circle. It then calculates the centroid along the reference vector from the reference point that fits the diameter so that it is equal to the input value.

If you use a Height construct type, the input value represents the distance along the reference vector from the reference point, which is the sphere centroid.

PC-DMIS uses the value points as the offset from the reference point along the reference vector. The resultant centroid and diameter are identical after the offset is applied.

To Construct a Sphere Circle

1. Access the Construct Circle dialog box (Insert | Feature | Constructed | Circle).

2. From the Method list, select the Sphere option.

3. Select one feature. The type must be a sphere.

4. Select either DIAMETER or HEIGHT from the Type drop-down list.

5. Type a value for the diameter or height into the Value box.

6. If you selected Height:

• Select a reference point from the Point list.

• Select a reference vector from the Vector list.

7. Click the Create button.

The Edit window command line for this option would read:

CONSTR/CIRCLE,SPHERE,feat_1,DIAMETER,REF_VECTOR = ZPLUS

or

CONSTR/CIRCLE,SPHERE,feat_1,HEIGHT,0,REF_POINT = SPHERE_CENTROID,REF_VECTOR = vector