Adding a New Interactable Object

Let's add a new type of interactable object that we can grab, hold, and throw (it will be inherited from the VRBaseInteractable component) with an additional feature: some visual effect (for example, smoke) will appear when we grab the object and, it will disappear when we release the object.

1. Create a new VRObjectVFX component and add the following code to it:

   Source code (C#)

   using System;
   using System.Collections;
   using System.Collections.Generic;
   using Unigine;
   
   [Component(PropertyGuid = "AUTOGENERATED_GUID")] // <-- this line is generated automatically for a new component
   public class VRObjectVFX : VRBaseInteractable
   {
   	// an asset with an effect that occurs when the object is grabbed
   	public AssetLinkNode vfx_node = null;
   	private Node vfx = null;
   
   	// this method is called for the interactable object each frame
   	private void Update()
   	{
   		// update transformation of the effect if the object is grabbed
   		if(CurrentState == VRBaseInteractable.INTERACTABLE_STATE.GRABBED)
   		vfx.WorldTransform = node.WorldTransform;
   	}
   
   	// this overridden method is called after component initialization (you can implement checks here)
   	protected override void OnReady()
   	{
   		// check if the asset with the visual effect is specified
   		if (vfx_node == null)
   		{
   			Log.Error($"{nameof(VRObjectVFX)} error: 'vfx_node' is not assigned.\n");
   			Enabled = false;
   			return;
   		}
   		else
   		{
   			vfx = vfx_node.Load();
   			vfx.Enabled = false;
   		}
   	}
   
   	// this overridden method is called when grabbing the interactable object
   	public override void OnGrabBegin(VRBaseInteraction interaction, VRBaseController controller)
   	{
   		// show the effect
   		vfx.Enabled = true;
   		// set the current object state to 'GRABBED'
   		CurrentState = VRBaseInteractable.INTERACTABLE_STATE.GRABBED;
   	}
   
   	// this overridden method is called when releasing the interactable object
   	public override void OnGrabEnd(VRBaseInteraction interaction, VRBaseController controller)
   	{
   		// hide the effect
   		vfx.Enabled = false;
   		// set the current object state to NOT_INTERACT
   		CurrentState = VRBaseInteractable.INTERACTABLE_STATE.NOT_INTERACT;
   	}
   }

2. Assign the VRObjectVFX component to the cylinder node (the child of the kinematic_movable dummy node).

3. Drag the vr/particles/smoke.node asset to the Vfx Node field. This node stores the particle system representing the smoke effect. It is available in the vr/particles folder of the UNIGINE Starter Course Projects add-on.

   

4. Save changes (Ctrl+S) and press the Play button to run the application.

Now, if you grab and hold the cylinder, it will generate smoke: