Editing Polygon Data
Time to read: ~4 min
Though the InStep Studio application is primarily focused on the conversion of mesh data to boundary representation data, there
are scenarios where it is beneficial to directly edit small sections of a mesh to obtain better a conversion. The Edit tab provides
access to manual tools for doing so.
In general, the Edit operations rely on a Select->Command->Accept/Reject order (so selecting a face then deleting it and only once Accept
is clicked does the change take effect). Selection and Un-Selection are accomplished through mouse-clicking an entity to select it and using
the Control (Ctrl) button together with a mouse-click to un-select it. By default, hitting the Esc key clears all active selections.
Selection of items (triangles, edges or vertices/points) is accomplished by selecting them in the main view.
The following buttons are shown:
- Defines how clicking on an item filters the selection with options for Faces, Edges or Points. When a
type is allowed, it is made visible. To hide those entities again, use the menu option View >
Visibility > Show Faces, Edges or Points
- The Boundaries toggle-button allows edges to be highlighted that are only connected to a single face. In
order to be considered a valid edge, it must be connected to exactly two faces.
- When a Face is selected, clicking Grow will expand the selection to the faces that are neighbors to the
selected faces by means of their shared edge.
- The Flood button expands the selected faces by continuously growing until edges are encountered that form
an angle between the two faces that exceeds the angle given in the text-box.
- Add Point
- The Add Point allows new points to be placed in the data. The available options to insert a point are:
- From Coordinate (enter the X/Y/Z location of the new point).
- Point to Surface projection (Note the status bar asks for inputs to be provided by selecting a surface, point and enter to accept).
- Center of Points (Allows selection of multiple points and then generates a point at their center).
- Pick on Surface: Allows point to be manually picked in the viewer.
The Delete button (Del key by default) removes any Faces from the displayed data. The data is only deleted from memory once the Accept button is pressed. If
data is accidentally deleted that should have been kept, it can be restored by clicking Cancel. Delete only works on Faces. Edges are updated to reflect
their use once the Accept button is pressed and Points are retained.
Note that the Delete button also acts as a toggle button. If nothing is selected and the Delete button is pressed, it is put in an active state
and any selections after this cause the item to be deleted. If an item is first selected, clicking the Delete button causes only the selected
item to be deleted.
Only faces can be created in the viewer (creation of points is done from the Selection menu as described above). Like the Delete button, the Create
button is a toggle-on/off button when nothing has been selected or acts on a single item once selections have been made. To create a face,
three points need to be selected. The order in which the points are chosen determines the direction the face will be pointing in (the Normal vector follows the
right-hand rule). Once created, clicking Accept generates the underlying data.
The Flip Normal button is also a toggle button when no items are selected or, once an item is selected, acts only on the selected
item. Flipping a face is sometimes required in order to correct local issues where the direction of the face has been incorrectly
determined. Usually, the Polygon tools can be used to automatically correct any issues, but in some cases the tools are unable to
determine the correct order and a manual correction becomes necessary.
Clicking the Accept button applies any changes made to the data stored in memory. This also updates edge associations and similar items
which is important for the integrity of the data.
Note that if changes are still pending (i.e. have not been Accepted or Rejected/Cancelled), the other tabs will not be enabled, forcing
the current tasks to be completed.
If any changes were made that were not intentional, clicking Cancel ignores them and reverts the data back to where it was
after the last Accept was performed.
The Measure tool provides a basic measurement tool to measure distance between two points (selected by clicking them
in the viewer). Upon clicking the first point, its location is shown.