### Constructing a Circle from a Cone

A circle can be constructed from a cone at a specified diameter of the cone, or it can be constructed at a given height from the current alignment plane. A Cone Circle feature at a given diameter is also commonly known as a Gage Diameter.

Understanding the Height Value

If constructing a circle at a given height, PC-DMIS calculates the circle in this way. It creates a plane from the reference point and the reference vector. It then creates a parallel offset plane from this plane by the height value. This parallel plane intersects with the cone axis, and the intersection creates the location of the resulting circle feature. The diameter of the circle is the diameter of the cone at that intersection point.

Available reference point (REF_POINT) options:

- CONE_VERTEX

- CONE_START

- CONE_END

- ORIGIN

Available reference vector (REF_VECTOR) options:

CONE_VECTOR

WORKPLANE

ZPLUS

ZMINUS

XPLUS

XMINUS

YPLUS

YMINUS

For example, if you use the origin as a reference point, and ZPLUS as your reference vector, PC-DMIS would create a plane from the origin point and the ZPLUS vector. Then it would create a parallel plane at the given height value, and where it intersects with the cone, it creates the circle feature. Your Edit window's code might look something like this:

CIR2 =FEAT/CIRCLE,RECT,OUT

THEO/-67.295,2.595,-7.152,0.0310723,-0.0214397,-0.9992872,29.411

ACTL/-67.295,2.595,-7.152,0.0310723,-0.0214397,-0.9992872,29.411

CONSTR/CIRCLE,CONE,CON2,HEIGHT,5,REF_POINT = ORIGIN,REF_VECTOR = ZPLUS

Procedure to Construct a Cone Circle:

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

2. Select the Cone option.

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

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,CONE,DIAMETER,feat_1

Or

CONSTR/CIRCLE,CONE,HEIGHT,value,REF_POINT=point,REF_VECTOR=vector,feat_1