Manipulating Vertices by drag and drop

[caroline]

Funnily enough, we were talking about this the other day - how to deal with taps and selection:

Detect tap on a mesh

To pick or “click” on a geometry items, you need to cast a ray (line-segment) out from the camera and then test against every triangle in the scene. This can be very expensive depending on the amount of geo / tries in a scene. To get around this there is a tree structure called an OctTree which is used to query regions in space. I would suggest looking into projection from screen space into world space, this will help with the creation of a line segment from camera into the world. Then loop ov…

Conceptually, OpenGL is much the same as Metal, and this suggests using colors:

How to select a vertex or triangle of a mesh in modern OpenGl (3.3 above)?