How does the 3d cursor work?

I’ve been using Blender for quite a while now, but I can’t for the life of me figure out the rules governing the left-click placement of the 3D cursor. While it does always appear under your mouse, the Z-depth is always entirely unpredictable. Sometimes it will appear on the grid. Sometimes right in front of the camera. Sometimes a looooong way off behind the scene. If I click the same place 5 or 6 times fron different view angles it will sort of appear in the general vicinity of where I clicked, but never with any precision. It also works works reasonably well if I use the quad-view orthographic projections, but I almost never work that way so it’s not much help.

For a while, I think around 2.55 or 2.56, it worked by snapping to the surface of whatever you clicked. I thought to myself “They finally fixed it! This is so awesome!”

But now with 2.58 I click and the cursor location is unpredictable again. Could someone explain to me the exact rules that govern the placement of the 3D cursor?

For a while, I think around 2.55 or 2.56, it worked by snapping to the surface of whatever you clicked. I thought to myself “They finally fixed it! This is so awesome!”

This is an option in the user preferences. I think its called ‘Autio Depth’

Oh. For some reason I thought that option had something to do with the viewport FOV. Since it appears under the “View Manipulation” header. Now I feel dumb.

Thank you very much for your reply!

It would still be nice to know what rules govern it in non-auto depth mode.

What I believe is that the movement of the 3dcursor is restricted to what you see in the 3dview. Basically from the 3dview’s POV the cursor can move horizontal and vertical, but not towards or away from the current view.

I think…

Oh. Just tested it and it seems to be the case. Thanks!

I probably never figured it out because I rarely had to place my cursor twice without changing the perspective.

Manually placing the 3D curser where you want it in 3D space is 2-step process. Use top view, without prospective, to place it in XY loaction. Then in front / side view, without prospective again, place it in Z.