InStep Studio


Fix OverlapsOverlap-Repair

Time to read: ~2 min

Overlapping sections are those that have been identified using the 'Issues' display as being self-intersecting. Generally, this may occur when a body contains multiple bodies that have not yet been separated. In other cases, this can indicate problematic geometry.
The Overlap repair tool attempts to address some of these surfaces though it is recommended that this tool be used sparingly as such overlapping geometry often indicates bigger issues that cannot reasonably be resolved in this way.

Example: Blender Monkey

Using the same example file as for other tools, the Blender Monkey (Suzanne) is being used. In the Issues tool, the full mesh was shown and the regions around the eyes shown as having intersections. A close up of one of these regions shows the issue:

Overlapping faces
Region of overlapping faces

From the image, it can be seen that there are a number of faces that intersect other faces. In this case, the cause is due to the eyes not having been correctly split into separate bodies (and separately healed). Irrespective of a better way of resolving this, by using the Overlaps tool, the preview shows the split faces:

split faces
Preview of repaired section

In many ways, this should be sufficient to continue using the data, however, the tool only splits intersections that it finds and does not directly modify surfaces that may have been attached to the original data. In some cases, this may be sufficient to allow further processing, however care must be taken to understand the underlying issue and to avoid it where possible.

Option: Heal Fractures

By turning this option on, the tool attempts to locate sections within the group of facets that are being modified where sections of open edges are generated. This may be the case when surfaces intersect in such a way as to allow curvatures of both groups to form isolated regions. Healing is generally recommended but may be more appropriate once the data has been generated and inspected for open edges/holes.

Option: Tolerance

Some of the splitting and re-forming of facets takes into account tolerances between locations (similar to the vertex merge option). If locations are generated that fall within this value (should be a small value only), then they are, where possible, collapsed to a common point.

Option: All, Selected, Preview, Clear & Apply

It is recommended to use the Preview button before permanently committing to a change. The Apply button follows the same process as the Preview but directly proceeds to implementing the changes. Clearing the Preview simply deletes the temporary display data. If there are multiple bodies, it is possible to use the tools on a per-body basis (for any selected items) or for all available data.