Inference locking is available in FormZ but I don’t believe is not mentioned as such in the FormZ Manual. It’s a term used in Sketchup to mean a system that locks your cursor along an axis in reference to any point, edge, guide, or face. In FormZ, inference locking is available while using the Guide, Draw, or Transform tools. I'll review each type before making a suggestion.
INFERENCE LOCKING TO A POINT:
To lock the cursor to any point in space (whether to a point on another object or to a point on the object you are drawing) you move your cursor along an X, Y, or Z axis and hold down the shift key. This "locks" your cursor along that axis. Then hover your cursor over any point of an object (Snaps ON or OFF) and a gray colored line displays perpendicular to the locked axis to that point, then click to execute.
This is identical to the procedure one uses in SketchUp.
See 01_Inference Lock_Point:
01_Inference Lock_Point_FZ.jpg 22.84KB 0 downloads
INFERENCE LOCKING TO AN EDGE/GUIDE:
FormZ does not have Inference locking to an edge however it does have cursor locking and snapping to a guide. This can be done fairly quickly. “Snap to Intersection” or the “Stick to Edge” option in the Snap Options should be ON.
When drawing or transforming, first create a Temporary guide (Ctrl+spacebar or Cmd+spacebar) over a point on the edge. Next, lock the cursor to an axis by holding the SHIFT key while moving the cursor toward the guide.
See 02_Inference Lock_Temoray Guide_Intersection Snap:
02_Inference Lock_Temp Guide_Intersection Snap.jpg 73.58KB 0 downloads
See 03_Inference Lock_to Guide Temporary Guide_Stick to Edges:
03_Inference Lock_to-Guide-Temp Guide_Stick to Edges.jpg 97.98KB 0 downloads
INFERENCE LOCKING TO FACE:
FormZ does not have an inference locking to a face plane as does Sketchup.
In the example below a V-line was drawn on the XY-plane and locked (with the SHIFT key) on the
X-axis. While holding the SHIFT key the cursor hovered over a face with an active custom plane (the Snap to Face was ON). The V-line attached to the cursor did not terminate at the reference plane of the face. The V-line projected past the object’s reference plane as shown penetrating the brown rectangle that was drawn on the object’s reference plane.
See 04_Inference Lock_Object Plane_FormZ for Example of Inference Locking to the Plane of a Face: (Not Available in FormZ):
04_Inference Lock_Object Plane_FZ.jpg 40.88KB 0 downloads
See 05_Inference Lock_Object Plane_SU for Example of Inference Locking to the Plane of a Face: (Shown above in SketchUP):
05_Inference Lock_Object Plane_SU.jpg 14.76KB 0 downloads
My suggestion is that FormZ add the features of Inference to Edges and Faces.
Inference locking.pdf 320.95KB 5 downloads