Showing standard gizmos in editor mode

Question

I'm writing an extension to Unity editor and was wondering if there's a way to show multiplbe gizmos for rescaling/moving colliders in the scene view while in editing mode? I don't want to re-invent the wheel and create custome gizmos (already started my ugly version!) Thank you!

Answer 1

I think you are speaking about Handles.

In the docs are examples on how t use them e.g. Handles.PositionHandle, Handles.RotationHandle and Handles.ScaleHandle.

Usually you should use them in OnSceneGUI.

Vector3 newPosition = Handles.PositionHandle(currentPosition, Quaternion.identity);
Quaternion newRotation = RotationHandle(currentRotation, position);
Vector3 newScale = ScaleHandle(currentScale, position, rotation, handleSize);

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However I would always recommend to rather use proper SerializedProperty to avoid problems with Undo/Redo and marking things dirty + saving etc.

Just an example (this won't override the Transform's default handles so it can get confusing)

using UnityEditor;
using UnityEngine;

[CustomEditor(typeof(Transform), true, isFallback = false)]
public class TransformEditor : Editor
{
    private SerializedProperty position;
    private SerializedProperty rotation;
    private SerializedProperty scale;

    private void OnEnable()
    {
        position = serializedObject.FindProperty("m_LocalPosition");
        rotation = serializedObject.FindProperty("m_LocalRotation");
        scale = serializedObject.FindProperty("m_LocalScale");
    }

    private void OnSceneGUI()
    {
        serializedObject.Update();

        position.vector3Value = Handles.PositionHandle(position.vector3Value, Quaternion.identity);
        rotation.quaternionValue = Handles.RotationHandle(rotation.quaternionValue, position.vector3Value);
        scale.vector3Value = Handles.ScaleHandle(scale.vector3Value, position.vector3Value, rotation.quaternionValue, 1);

        serializedObject.ApplyModifiedProperties();
    }
}