Often, users should or could use the Pierce relation in Onshape to define relationships between entities in a sketch instead of using a Coincident relation. The objects could be in the same sketch, in different sketches, or between a sketched object and an existing edge of the part.
Pierce Between Sketched Items
When defining relations between sketches, users are sometimes confused about the difference between a Pierce and a Coincident relation.
In the example below, when trying to align two curves that exist in separate sketches, the Coincident relation only places a vertical constraint between the points.
To ensure that the point in the second sketch follows the curve from the first sketch, you need to use a Pierce relation. This fully defines the sketch point, as shown below:
This also allows you to use the first sketch as a guide curve between the profiles when creating a Loft between the profiles:
Also, use Pierce to position a profile for a sweep:
Pierce Between Sketches and Part Edges
Additionally, use the Pierce relation to position a sketch profile along an edge. By choosing Pierce instead of Coincident, the sketch is fully defined with only one constraint.