How to control the coordinates of newly created gameobject

Archived Forums Questions & Answers
1

I want to nullify the z-coordinate for all new gameobjects that get created.
I try produce the following behaviour:

  • Copied gameobjects inherit their z-coordinate
  • Gameobjects that are dragged from the project view to the scene view get a 0 z-coordinate while being dragged into the scene
  • Once a gameobject is dropped (mouseUp), I can modify the z-coordinates again, even by dragging in the scene view
2

Never actually needed something like you need, but I have two tips that should help:

  • if you use CTRL+ALT+SHIFT while dragging an object into the scene, it will attach to surface. It will actually follow geometry so as to allow perfect positioning and stacking
  • I’m certain you can ‘intercept’ instantiation by means of an editor script (for example the assetpostprocessor intercepts asset import), but sadly I don’t know the right routine you need for this case.
3

We did this in our project. A Scene object has to be selected for it to work, but it’s useful. It speeds up our scene construction process.

import UnityEngine

[CustomEditor(Scene)]
class SceneEditor (Editor):

    scene as Scene

    def Awake():
        scene = target as Scene

    def OnSceneGUI():
        if Event.current.type == EventType.Repaint:
            # draw scene-mode warning in scene window
        if Event.current.type == EventType.DragPerform:
            for r in DragAndDrop.objectReferences:
                o = EditorUtility.InstantiatePrefab(r)

                go = o as GameObject
                go.transform.parent = scene.transform
                zeroGround = 0f

                ccam = Camera.current
                mouseRay = ccam.ScreenPointToRay(Vector3(Event.current.mousePosition.x, ccam.pixelHeight - Event.current.mousePosition.y, 0.0f))
                if mouseRay.direction.z > 0.0f:
                    t = -mouseRay.origin.z / mouseRay.direction.z
                    mouseWorldPos = mouseRay.origin + t * mouseRay.direction
                    mouseWorldPos.z = zeroGround
                    go.transform.position = mouseWorldPos
            Event.current.Use()
            DragAndDrop.AcceptDrag()