## Detecting the Intersection of Two Bodies

The method

```cpp
MbResultType InterferenceSolids(MbSolid &                   solid1, 
                                MbSolid &                   solid2,
                                std::vector<MbCurveEdge*> * edges,
                                std::vector<ptrdiff_t> (*faceNumbers)[4])
```

evaluates the intersection of two bodies.

The method input parameters are:

-   **solid**1 is the first body,

-   **solid**2 is the second body,

-   **edges** are the body intersection edges (no edges is also a
    possible situation),

-   (\*faceNumbers)\[4\] is the face number container (it can be empty).

The output parameters of the method are the intersection **edges** of
**solid**1 and **solid**2 body faces and the numbers of intersecting
faces (\*faceNumbers)\[4\].

The method returns either rt_Intersect if the bodies intersect or
rt_NoIntersect if the bodies do not intersect.

The method is declared in the *cdet_bool.h* file.

The method modifies the **solid**1 and **solid**2 body edges, so if you
need to keep the bodies unchanged, then you should pass to the method
the copies received using MbSolid::Duplicate(). The bodies are modified
by cutting the edges of the bodies with intersection edges.

The returned value, rt_Intersect, means that the pair of bodies has some
intersection volume or some contact area. The function returns
rt_NoIntersect if the bodies have no intersection volume. The tangency
at one point is not considered to be intersection as in this case
intersection volume is zero.

If the pointer to the **edges** container is not NULL, then the
**solid**1 and **solid**2 intersection edges will be added to the
**edges** container.

If the pointer to the faceNumbers face number container is not NULL,
then the numbers of the intersecting faces of the first and second body
correspondingly will be added to faceNumbers\[0\] and faceNumbers\[1\].
Furthermore, the numbers of the contacting faces of the first and second
body correspondingly will be added to faceNumbers\[2\] and
faceNumbers\[3\].