Written for Version 0.19
The Sketcher Horizontal Constraint fixes the Y Axis value of two or more Points ( vertex_) to be equal to each other.
The two vertices are generally the end points of a single line. However, any two vertices can be used.
Some Qualifying Vertices
- End of a Line
- Center Point of a Circle
- Center Point of an Arc
- Corners of Rectangles
Curved Edges cannot use the Horizontal constraint and you will receive and error message:
In order to use the constraint, and for the tool to be active you need a sketch in edit mode. The constraint can be applied to a selected vertex or edge and used to select edges.
Application of the Constraint
If the constraint is used on an edge it will set the Y value of the Second Vertex to the Y value of the First Vertex.
Given the above edges applying the Horizontal Contraint will in the case of the line formed by Vertex1 and Vertex2, the line will be horizontal at the Y Axis position of Vertex1. For the second line the Y Position of Vertex 3 will be used.
You can see the result in the following figure.
It is possible to determine the numbering of the vertex by hovering over the vertex and checking the Status bar on the bottom of the application window.
If more than one line is selected the constraint will be applied to all lines.
Selecting a Vertex.
Vertex must be pre-selected to be used by the Horizontal Constraint tool. As shown below the Horizont constraint will only apply to edges.
When hovering over the vertex of the circle the element is filtered out. The tool will not allow the selection of a vertex this way. You will need to pre-select the vertices then select the constraint tool.
When the constraint is used on vertices, all vertices are adjusted to the first selected vertex.
Selecting the center vertex first, will align the outer two circles to the center circle:
Applied to the control nodes of a B-Spline
NOTE: In FreeCAD the Y Axis and X axis are referred to internally as the V_Axis and H_Axis respectively