Sketcher ValidateSketch

Description
The Validate sketch utility can be used to analyze and repair a sketch that is no longer editable, has invalid constraints, or to add missing coincident constraints to a sketch created from imported geometry such as DXF files. It can also be useful to locate a missing coincidence in a native sketch that generates a "can't validate broken face" error when trying to apply a PartDesign feature.



Usage

 * 1) Select the sketch to validate, either from the Model tree, or by clicking on one of its edges in the 3D view.
 * Note: the sketch must not be in editing mode. If you are in sketch edit mode, you need to use the button, or the  button at the top of the Tasks tab.
 * 1) Open the validate sketch utility either:
 * 2) * from the dropdown
 * 3) * pressing the [[Image:Sketcher_ValidateSketch.svg|24px|link=Sketcher_ValidateSketch]] button in the [[Image:Workbench_Sketcher.svg|16px|Sketcher_Workbench]] Sketcher_Workbench.
 * 4) See Options below for operation.
 * 5) Press the  button when done.

Missing coincidences
Finds out missing coincidences for overlapping vertices, and adds them. Press the button; a pop up dialog will appear to report how many missing coincidences were found; they will be shown in the 3D view as yellow crosses. Press to close the dialog, then press the  button to add the missing coincidences.

If necessary, define a larger tolerance value in the drop-down field.

Press to highlight vertexes that are outside this tolerance.

This tolerance is also used by the / process as well.

Leave the "Ignore construction geometry" checkbox checked to disregard construction geometry in the analysis.

Invalid constraints
Checks for malformed constraints.

For example, if there is a Circle-Line-Tangent constraint, but it references two lines, it is considered invalid.

(This sometimes happens due to the Toplological Naming Problem, i.e. the external geometry changes type).

It also does other checks, such as for empty links.

Degenerated geometry
Degenerated geometry can result from solver actions in a sketch.

For instance, if a line is forced to shorten to become almost a point.

Other examples: a zero length line or zero radius circle/arc.

Reversed external geometry
Reversed external geometry can happen because the handling of reversed geometry was changed around revision 0.15.

This process might be helpful if sketches with external-geometry fail to solve because of these changes.

Constraint orientation locking
Tangent and perpendicular constraints are implemented (via-point).

Internally they work by constraining the angle between tangent vectors. With tangent constraint for example, the angle can be 0 or 180 degrees (co-directed or opposed vectors). The actual angle is remembered in the constraint data ("constraint orientation is locked"), it guards against flipping. But the angle can be erased ("constraint orientation unlock") or updated; these tools do exactly that.

The locking mechanism typically works well and this tool should not be needed. It should only used after making a backup of the open document.