I'm pretty new to Unity and im working on a duo project with my friend. He is generating a city with L-system, with prefabs made in MagicaVoxel, and I'm trying to populate the city with pedestrians and make them walk randomly.
I have the NavMeshComponents from git, and my problem is i can't bake the navmesh on runtime because the objects (roads houses etc.) are instantiated and pieced together on runtime. All the tutorials I've seen had object before running so they could put the navmeshsurface on it, but in this case i can't. Is there a solution for this or i should try to find a different approach? Thanks for the help.
To use the navmesh baking at runtime you need to create a empty GameObject that holds a NavMeshSurface component.
Then in your script, access that component and bake it whenever you need
using Unity.AI.Navigation
void BakeAtRuntime()
{
GetComponent<NavMeshSurface>().BuildNavMesh();
}
Related
I'm working on a small project where the goal is to defend yourself from mass enemy hordes in a 2d environment. The goal is to have the game be physics based, with enemies pushing against eachother to create a feeling of chaos.
Now I have a setup with enemies, a player and multiple obstacles all with a Rigidbody2D and 2D-colliders (mixed types, including polygon2D collider). Now I want to have the enemies chase the player. The obstacles however are polygon shaped rigidbodies, and thus are able to move.
So I want the "navigation" mesh of some sort to update on the fly, and calculate a navigation path for many entities.
Note: I don't know how many entities yet, but let's say ~100.
The things I tried to far:
Using the built-in NavMesh package from Unity. This package does not properly support the 2D configuration of Unity
Using the NavMeshPlus package. This implements a NavMeshSurface2D component to work with the 2D environment. I got this to work, but the NavMeshAgent component to steer the enemy does not use the force attribute of the rigidbody component, but rather just sets the speed or position of the transform. If someone knows how to use the NavMeshAgent or the NavMesh API in a way to get the target direction/speed via script, that would also be a solution
I tried the A* package. Which also works, but creates a very jagged line as it only can move in 8 directions (up,down,left,right and diagonals). It also cuts the corners of the obstacles, and does not take into account the size of the object (enemy) itself, so it hangs at the corners.
If anyone knows a good package/extension or the location of documentation of the NavMesh part, that would be great!
Thank you in advance.
So I got it to work and will share the solution I took:
Using the NavMeshPlus package, I created a navmesh.
Instead of using a NavMeshAgent, I configured an agent type in the navigation window with the right physical dimensions.
Next I added a script on the enemy to function as a custom NavMeshAgent.
Add a NavMeshSurface2D reference to the script (Serialized)
Using UnityEngine.AI, call NavMesh.CalculatePath(), with the AI.NavMeshQueryFilter. This has 2 components, the agent and area setters. Both of those I get from the NavMeshSurface2D reference.
Now you have the path the agent has to follow!
By the way, I'm also aware this could be done by a custom Agent inheriting the NavMeshAgent class, I'm also looking into that. Time will tell which one will have better performance.
Whenever I need to instantiate prefabs, I always use the following technique
Add a GameObject/MonoBehaviour field to the MonoBehaviour which would instantiate the prefab.
Use this field to instantiate the prefab
E.g.:
public class ExmapleController : Monobehaviour
{
[Serializefield]
GameObject _examplePrefab;
GameObject _exampleObject;
public void SpawnExample()
{
_exampleObject = Instantiate(_examplePrefab);
}
}
Now my problem with this is that first of all I need two references. One for the prefab and one for the instantiated object. Secondly, whenever I need additional prefabs I have to create new and new references inside my script. This sometimes clutters my Scripts and I always wonder that is this memory efficient? What does Unity do behind the scenes? It just only stores a GUID reference for my prefab than somehow loads this prefab based on this reference? Or when I make a prefab reference the whole object tree is pulled into memory and I should rather use Asset bundles or another Unity technique?
Basically that's fine. But if you want to improve your workflow you can try creating ScriptableObjects to store the prefab references and then have only 1 reference to your scriptable object inside the mono behaviour. It will help you keep your mono behaviour classes clear. For more advanced approach you can check Dependency Injection frameworks for Unity. The most common one is Zenject. It helps you in managing dependencies in your classes (prefabs in your case are dependencies of Monobehaviour class).
When you create a reference to a Prefab Unity only store the GUID of the prefab you referenced. It is how resource system in Unity works. But if your prefab is required on the current scene then it will be fully loaded with all inner dependencies. If loading takes much time than it is the reason to think about using Addressables (AssetBundles). Unity doesnt have any other technique to avoid loading the full object tree in memory. But addressables let you control when to load the specific prefab from asset bundles to memory.
Yes this perfectly fine and how it's done. A reference is just that: a reference. The only time a copy of the object is made is when you call Instantiate.
If you have multiple prefabs that are just variations of one you should use ScriptableObject instead and have just 1 prefab that can take any variation form. You would still intantiate them the same way.
Basically that's fine. But if you want to create a huge numbe of objects or delete them you could also have a look at Object Pooling. More infos can be found under the link from the tutorial at Unity:
https://learn.unity.com/tutorial/introduction-to-object-pooling#
"Object Pooling is a great way to optimize your projects and lower the
burden that is placed on the CPU when having to rapidly create and
destroy GameObjects. It is a good practice and design pattern to keep
in mind to help relieve the processing power of the CPU to handle more
important tasks and not become inundated by repetitive create and
destroy calls. (Unity)"
I have a pool of objects, this object are some prefabs, but I can not find the way to do it navigation -> bake work, there is some way to apply thebake to prefabs, or plicate it at run time.
Currently the alternative I am using is to apply the bake to an object in the unity editor and move it where the new part of the pool appears, In the same position, to be able to use the navmesh.
I would like to know if the comment is possible, or if not, the last would be a good alternative, or which would be a good alternative?
I'm sorry for my bad english, I hope you can understand me
Use Unity's advanced features, which is the "NavMeshComponents", you can bake a prefab into a single navmesh and use navmesh link to connect between those prefabs.
There's a github demo about this you can check. I've used that and it works fine.
https://github.com/Unity-Technologies/NavMeshComponents
In my unity3D project I have a manager script that should take care of initializing a game level, instantiating and placing all relevant prefabs. However, I can't find a way to instantiate a prefab by its class - it turns out that "instantiate" really means something more like "clone" in Unity3D. So as a workaround, I had to make my manager script a MonoBehaviour, attach it to an empty object and assign my prefabs to it from the inspector since it is the only way I have found to make it work at all. This looks kind of awkward. Is there any way to actually instantiate a prefab, without cloning it from a reference?
You can load prefabs at runtime. Just have a look at the script reference which comes with examples:
http://docs.unity3d.com/Documentation/ScriptReference/Resources.Load.html
Here is an article that should clarify how it works:
http://docs.unity3d.com/Documentation/Manual/LoadingResourcesatRuntime.html
I'm creating a randomly generated terrain game where an enemy will follow after you. The terrain is built after launch through UnityScript. I am using Nav Mesh Agent for the enemies path finding but it is unable to find its way around the newly created objects. Is there a way to update the Nav Mesh after launch to accommodate the new objects? Thanks in advance!
Aside from plugging someone else's asset store product, have you looked at the NavMeshObstacle component? It's intended for dynamic obstacles for avoidance with NavMeshAgents.
And no, you cannot (nor should need to) rebuild the NavMesh at runtime.
As far as I know you cannot rebuild navmesh.
Maybe you should try with Astar pathfinding project http://arongranberg.com/astar/. It's great and used in a lot of commercial games. Free version has option to rebuild navigation graphs.
For next questions about unity3d try here.