Rendering order: In front of world space, but behind the UI

What I want is fairly simple. I want to make it so that, if a player clicks on an enemy, a little targetting box appears around them. I can do this for the most part, but the problem I have is that it renders behind other 3d objects depending on their location along the Z-Axis. For instance, if I'm in front of the targetting box it will look like this:


And if I'm behind it it will look like this:


Almost like it's a real object in the world. While I want it to be a real object in the game world that can't be interacted with, I don't want it to LOOK like it. I want the square to render in front of everything in the scene regardless of where it is, but at the same time it has to render BEHIND everything in the UI (which shouldn't be a problem because it's not something that should exist in the UI to begin with).

I've heard something about sorting layers, but I've tried using them and haven't been able to get anywhere with them and it seems like they're only for whether or not they're rendered in front of other 2D elements or not and not whether or not they're rendered in front of 3D elements. I've also heard a shader can fix this but I know next to nothing about shaders and would like to avoid using them if it can be helped.

 

Not completely sure, because I don't have Unity to test it right now, I will check it tonight:

You don't need shaders for this, it's indeed about the rendering order of the different objects. You can create a layer for this 'selection box'. Now create a second camera and make the second camera render this layer. The primary camera should not render this layer.
The second camera should be drawn on top of the first one. That way this object will always be on top of the others.

http://answers.unity3d.com/answers/17842/view.html gives the same solution in case my explanation was not clear.

Every object that should then be drawn on top of everything else should have this new layer.

 

I have no idea how to do any of that, though.

 

Use two cameras. One camera renders the world objects. The other camera renders the targeting retical. You can use layers to filter out what each camera renders.

The cameras can literally be siblings of each other (ie have the same parent) and should move together.

Have the targeting camera always draw on top of the world camera. Then have the HUD draw last over both of those.

 

I just realized I restated the above solutions.

Basically, have a parent game object. Give it two children game objects. Then put cameras on each of those objects.

When you want to move the cameras, move the parent. Both children cameras will move along with it.

On the camera itself, if you look in the inspector there is a "Culling Mask" setting. This will tell it which layers to show.

Each game object has a "Layer" setting on the top right. This works with the Culling Mask of the cameras.

Cameras have a "Depth" setting which controls in what order the cameras draw to screen.

 

Ok, that certainly did SOMETHING, but the opposite of what I want. Now the box is rendering behind the character regardless of where he is instead of in front of the character regardless of where he is.

 

It also only applies for the character being in front of it. It still behaves normally when it's in front of other objects.

 

Nevermind. I fixed it.

 

Using two cameras just for a red box is overkill and may cause problems down the road. A simpler way is to go to the material you're using for that box, change the shader to something like "Sprites/Default", and then change the "Render Queue" dropdown to Transparent or Transparent+1000. Then you can go back to just using one camera.

 

It's not just for the box, but the content it's suppose to handle is fairly sparse. This is just a temporary solution so I have something to show my game meetup group. I'm planning on using a shader for this eventually because that seems like it'd be less of a headache in the long run, but I have no idea how shaders work for the time being.

 

Why not just put the targeting reticle's container in the UI below the other UI elements?

 

Because it has to be able to track objects that exist in world space.

 

That's not an issue. Just use Camera.WorldToScreenPoint and then feed that into RectTransformUtility.ScreenPointToLocalPointInRectangle to set the value to overlap the game object you want to track.

I'm assuming you're going for something like this (12:45):

 

Sorry for the necro but I see no crazy simple answer here.
For the record when making a target in 3d space or some other UI element that is in the same 3D space as non-rect transforms; just remember to use World Space setting on Canvas and set the order layer on the Cavas to some large number.