### Using the ProEngineerApertureRadius Entry

This entry determines the aperture radius, in pixels, that controls whether a ray is close enough to an edge for the edge to be selected from the ray hit.

Replace the default value of 7 with the needed value in terms of pixels. If the value is less than or equal to zero, then the function uses the default value of seven, or the current value stored in the configuration file.

- The intersection algorithm used by the PC-DMIS Direct CAD Interface for selecting and piercing Pro/ENGINEER part geometry returns a list of ray intersections with a model. It computes the intersection points of both the original ray and its "negative" with the geometry of the model. The output array is sorted in order of increasing signed distance. You must determine whether the ray is inside or outside the model.

- If a ray hits in the middle of a face on the model, the algorithm selects the face. However, if the intersection point is very close (within an internally determined selection aperture) to an edge, then the algorithm also selects the edge. Thus, more than one entry of type surface or edge in the ProSelection array may correspond to one actual piercing of the model by the ray. These multiple selections can decrease computation and comparison time.

- The smaller the aperture radius, PC-DMIS will return fewer intersections. This can improve computation and comparison time.

This value is located in the [ProEngineer]section of the Settings Editor. See "Setting Advanced Registry Options: Introduction" for information on changing Settings Editor values.