[Solved]Can Snap middle point be used in TechDraw?

[JamieRen]

I need use a lead line to show the ray goes through a glass prism. generally the ray goes will at the center of each surface so the leader line need show in the middle point of each line section, this is show in the attchment in red circle.

I can use leader line drawing a line at about center but it is not the exact middle point. so is there a way to snap a middle point to draw the line more accurately?

FreeCad version 0.21

[domad]

Greetings to the Community!
@JamieRen
Use the "Add Center line" function in the face or between two lines or between two vertices (drop-down choice), the gif shows how to do it.

[domad]

Greetings to the Community!
@JamieRen
...I add to what has already been suggested and shown, that it is possible, through the submenu of the "Add cosmetic vertex" button, to create cosmetic vertices central to lines/arcs/circumferences, then create the cosmetic lines using/joining these vertices.

[JamieRen]

Greetings to the Community!
@JamieRen
...I add to what has already been suggested and shown, that it is possible, through the submenu of the "Add cosmetic vertex" button, to create cosmetic vertices central to lines/arcs/circumferences, then create the cosmetic lines using/joining these vertices.

@domad
you solution solve my question perfectly!thank you very much! have a nice day!!