How make UI elements for 3d objects

News & General Discussion
1

I whant to make ui elements for some 3d objects. Its ui elements must hide if special 3d objects not visible in camera. Screenshot by Lightshot.
I mad ui elements in canvas. But I dont`t know how detect some 3d objects visible or not in camera

2

I don’t have experience in this, but these might help:
https://docs.unity3d.com/ScriptReference/Renderer.OnBecameInvisible.html
https://docs.unity3d.com/ScriptReference/Renderer.OnBecameVisible.html

3

It`s help in detect visible gameobjects by camera, but not detect is gameobject behind come other gameobjects

4

Maybe if you raycast from camera towards object with UI:
https://docs.unity3d.com/Manual/CameraRays.html
And then you compare object wih UI and object the ray hit. If they aren’t the same, you hide UI.

5

Raycast from camera to the object, and if the ray hits something before hitting the object, assume the object is not visible.

6

Thank you. But it`s work if objects full obstructed other objects. If big object and befor its small objects raycast may return small objecst

7

If it’s getting that complicated, why not make UI a part of 3d scene by moving canvas to worldspace?
Now when object is obstructed by a bigger object entirely, UI will also not be visible. You will, however, have to update UI’s Z position to object’s distance to camera on every frame if you have a moving camera (or object).

Edit:
And today I learned neginfinity has blocked me =D

8

Uh, fire multiple raycasts to cover object’s visible surface in a grid, and if they all hit something else, assume the object is not visible.

–edit–

It is possible to detect visibility with pixel-perfect precision, of course, but it will involve using compute shaders and for most practical purposes is an overkill.

9

It’s old-school, but one method is to render a colour-keyed version of the scene to a texture, then use that texture to decide what’s visible.