The 2023 version of SA added additional extraction methods for circles and slots to simplify hole extraction. These methods are based upon a standard developed for Volkswagen (VW) to facilitate automotive applications.
These extractions are available through the use of the right-click Configure Cloud Trapping Filter option. The reference or input cloud is saved and extractions are performed from this reference. This extraction process will build additional clouds within the GR Circle as show here:
The first option within the Extraction Method dropdown list is for 3D interior data which is a direct filter option:
3D Interior Data. Provides the original interior cylinder extraction data only. This method typically needs an additional projection plane reference within the GR-Circle. It uses the Z Minimum, Z Maximum and R Proximity settings in the extraction process.
3D Hole. This method provides a complete 3D hole extraction.
It offers the ability to extract a ring of data around a hole to define a local plane as well as extracting data from within the hole. It is assumed that the hole direction corresponds to the surface normal direction. The interior data is then projected to this local plane for the fit. The offset and width of the surface data can be set to define the local plane fit and the offset and width / height of data down inside the hole can also be set:
Offset | Bandwidth | |
---|---|---|
Surface Data: | Surface offset defines the space in (a) above between the extraction cloud and the nominal circle. | Surface bandwidth defines the width of the ring of data to be used for surface analysis to define the projection plan. |
Interior Data: | Interior offset defines the space in (b) above between the extraction cloud within the inner cylinder and the nominal circle. | Interior bandwidth defines the depth of the data considered within the hole for the cylinder extraction. |
A 3D Hole extraction will create a set of 3 separate extraction clouds in the tree (white clouds) in addition to saving the reference to the input cloud (pink cloud):
BestFitPointCloud VW - defines the cloud points used for the circle fit
InsideCloud VW - displays the cloud points detected along the inner cylinder face
RingBandCloud VW - displays the points on the top surface used to define the local projection plane.
The 3D Hole extraction process follows the following steps:
The RingBand cloud is extracted and used to fit a local plane
The InsideCloud is detected and then projected onto the local plane. This generates the BestFitCloud.
2D Hole. This fit methods is for sheet metal applications or other situations where data cannot be measured within the hole.
Only the Surface Data Offset and Bandwidth controls are used in this extraction method. A local plane is still extracted to define the surface orientation but only the boundary points are used to define the diameter of the hole. The boundary points represent the extents of each scan line and are saved as the BestFitPointCloud VW along with the RingBandCloud VW.
3D Plunged Hole. Plunged holes are different from 3D holes in that the interior data is now above the projection plane and projected down onto it. Try this option as well if the nominal is not oriented correctly when trying to extract circles or slots using the 3DHole method but it seems to fail.
2D Plunged Hole. This method first establishes a local set of data for projection plane and then projects all the data to this plane and extracts using the boundary points, much the same as a 2D hole.
3D Hole in a Surface. This method provides an option to work with curved top surfaces rather than a planar surface:
3D Plunged Hole in a Surface. Provides an option to extract data from a flange above a curved surface and uses the data within it to define the circle diameter.
2D Plunged Hole in a Surface. The same except only the boundary points are used to define the diameter.