How to repeat:
Set Transformation Orientation View to “View”.
Press G to start grabbing.
Select a vertex, Press X twice, it works, the vertex move along screen view x axis.
Select a vertex, Press Y twice, it works, the vertex move along screen view Y axis.
Select a vertex, Press ZZ twice, it doesn’t works ! The blue line points to some arbitrary bullcrap area and the vertex will move along that line instead…
The ONLY TIME ZZ works is when you view selected which will make you zoom in to a single vertex and then ZZ will work, this is ridiculous !
XX and YY works without having to zoom in to a single vertex !
I don’t know. It’s not a simple thing, because perspective space’s Z axis isn’t globally orthogonal to its X and Y axes-- a grab in a perspective transformed space would have more than just a translation component, but scale and maybe shear as well. I wouldn’t be surprised if a dev thought about how to implement a perspective-space shift-Y-Y grab and said, screw it, orthogonal view transform is enough.
The View orientation is based on the vector of a camera’s focal and pivot point. If the pivot point isn’t on top of the vertex, the vertex will never hit the point of convergence and instead follow a slightly different vector. It will still be in the camera’s vincinity. Relatively.
If you want the vertex to perfectly align to the camera in perspective mode, you need to have the pivot exactly on top of the vertex, i.e use View Selected.
Orthographic view is different, because there is no converging point for the vertex to aim towards, so it will always appear to stay in place when moved on the ZZ.
Yes I noticed it works in perspective if I “zoom to view” selected, but zooming “into” a vertex makes you too close to the subject, is there a way to zoom out ALONG the “point of convergence” ? If there is, this is SOLVED !