[FEATURE] Measuring / ruler tool

[burunduk3]

Please add a tool, similar to one found, for example, in prusa-slicer, which allows to:

• (basic) Select two objects (points, edges, surfaces) and show distance between them (and maybe coordinates of vector from one to another).
• (advanced) Select a circle (this is the advanced part, given that meshes don't have real circles, only approximations), show its radius and use its center as a selected object.

[ptsouchlos]

Screenshots would be helpful as I'm not familiar with prusa-slicer

[burunduk3]

[knoppix2]

To do this in a good manner, I think it needed to render the model in some backbuffer, where every surface has own color index (no lighting, etc). Then when the user picks up a point on the screen we could decide if:

1. pick the surface where the user point's to, indexed by color
   1.1) on that surface stick to the edge or to the vertex
2. find the nearest edge and stick to it
   2.1) decide if stick to the edge (minimal distance) or to the vertex

The method of rendering the colored surfaces allows some speed when picking, but the other options anyway requires calcularions. So, I'm no sure if it makes a lot of sence to implement rendering of a model to some back color buffer

[Smit-tay]

I'm an absolute newbie to the entire CAD universe, no doubt there's an issue here that I don't understand.
BUT - it seems to me that being able to select (click) points for a measurement to be made is absolutely basic functionality.
I imagine almost everyone who gets to the point of viewing an STL file wants to make some measurements.

[knoppix2]

Of course. But somebody must implement this feature.

[Smit-tay]

Of course. But somebody must implement this feature.

Indeed. Unfortunately, I am not the right person for this job.
I have so little experience with this whole topic that I wouldn't know where to start.
I'm pretty experienced with C++/QT, but nothing to do with CAD.