When you are editing a Sketch entity on page 172, some constraints inferred at the time you created the entity are recomputed to aid in editing the entity.

When you are editing a Sketch entity on page 172, some constraints inferred at the time you created the entity are recomputed to aid in editing the entity. See Sketch Inferencing on page 162 to learn more about the types of inferences. These temporary constraints work together, so that editing one entity can affect many other entities. The following list considers each inference described in the Sketch Inferencing section and discusses whether the inference will produce a constraint at edit time or not.

■ **Coincident Point Inference**

This inference results in a temporary constraint at edit time. If two entities share a point and that point is moved, it will affect both entities.

■ **Point-On-Curve Inference**

This inference results in a temporary constraint at edit time. If one entity has a point that lies on another entity, moving the second entity will affect the first entity. In case the entities are lines, editing the reference line will adjust the constrained line such that it maintains its direction, but still has an endpoint touching the reference line. In some cases, you can move the reference line in such a manner that the constrained line segment no longer touches the reference line segment, but it still touches the infinite line that the reference segment is part of.

■ **Midpoint Inference**

This constraint does not result in a temporary constraint at edit time. If you had a line whose endpoint was the midpoint of a second line, changing the length of the second line will have no effect on the first line, although the midpoint is now changed.

■** Sketch Grid Inference**

This inference does not result in any kind of constraint at edit time. If you change the Sketch Grid on page 138s snap values, it has no impact on any existing entity.

■ **Tangent Inference**

This inference results in a temporary constraint at edit time. If a line was created such that it was tangent to a circle, then moving either endpoint of the line will adjust the line and the circle such that the tangency is maintained.

■** Perpendicular Inference**

This constraint does not result in a temporary constraint at edit time. If you created a line such that it was perpendicular to a circle, the perpendicular relationship wont be maintained on editing either entity.

■ **Horizontal Inference**

This inference does not result in any kind of constraint at edit time.

■ **Vertical Inference**

This inference does not result in any kind of constraint at edit time.

■ **Parallel Inference**

This inference does not result in any kind of constraint at edit time.

**Removing a Constraint**

An inferred Sketch constraint cannot be removed through any user action. The only way to remove it is to delete one or more of the Sketch entities that participate in the constraint.