knife tool to snap perpendicular

Support Modeling
1

  1. When using knife tool , when i pick the second , how can i snap perpendicular the target edge ?

  2. how can i loop slice only to selected faces ?

Thanks

2

The knife tool operates on a point to point basis. It doesn’t understand perpendicular or target edges. Add some construction geometry. If you need perpendicular, or right angle cuts. Add a plane, position it where you need it, and snap to its vertices to define the cut. Then just delete the plane.

3

IIRC this has it:

4

If you hit “C” you can have some control on axis depending on the current view (in reality it is a 45 ° increment )… but for real control on it, you need use the snap method.

https://wiki.blender.org/index.php/Doc:CZ/2.6/Manual/Modeling/Meshes/Editing/Subdividing/Knife_Subdivide

now snap utilities addon is nearly perfect for this.