ObjectARX: Tolerance-公差

[StructLayout(LayoutKind.Sequential), Wrapper("AcGeTol")]
public struct Tolerance {
}

Description
This .NET class wraps AcGeTol ObjectARX class.

This is an instantiable class that is by default initialized to the default tolerances. Subsequently, the tolerances within it can be customized to suit a specific need. For example, an instance of this class may be specialized for use during surface intersection.

Class Tolerance keeps two properties, EqualPoint and EqualVector, which are used in evaluation according to the following rules:

1. Two points, p1 and p2, are equal if 

(p1 - p2).length() <= equalPoint

 

2. Two vectors, v1 and v2, are equal if

(v1 - v2).length() <= equalVector

 

3. Two vectors, v1 and v2, are parallel if

(v1/v1.length() - v2/v2.length() ).length() < equalVector
OR
(v1/v1.length() + v2/v2.length() ).length() < equalVector

 

4. Two vectors, v1 and v2, are perpendicular if
abs((v1.dotProduct(v2))/(v1.length()*v2.length())) <= equalVector

 

5. Two lines or rays are parallel (perpendicular) if their directional vectors are parallel (perpendicular)

 

Notes
Two lines are equal as point sets if, for any point on any line, there is a point on the other line within the EqualPoint tolerance from the first point. This implies that two lines with common point and parallel directional vectors are equal as point sets in the portion of the modeling space of DIAM, if only the tolerance EqualVector is set tighter than EqualPoint.