Raycast for strategy game not working

Hello everyone

I have an issue with a raycast
I did the following

Code (CSharp):

1. Ray ray = cam.ScreenPointToRay(Input.mousePosition);
2. RaycastHit hitData;
3. if (terrainCollider.Raycast(ray, out hitData, 200))
4. {
5.      buildingToCreate.position = hitData.point;
6. }

My problem is that my building is never exactly where my pointer is, or rarely
It s like if there was a mistake increasing or decreasing depending of the position

here it s almost (but not totally) good



Here it s worst



Any idea how to fix this ?
I have the impression it s maybe due to my camera



Thanks for your help and time
Vivi

 

I would forego the impressions and start sticking some debugging instrumentation in there to print data out in realtime, then pause the editor and study where the house ends up, see what varies.

In general to track down these sorts of things, I recommend liberally sprinkling Debug.Log() statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

- is this code even running? which parts are running? how often does it run?
- what are the values of the variables involved? Are they initialized?

Knowing this information will help you reason about the behavior you are seeing.

 

Well i did Debug.log. I m not a newbie
and yes the code is running, and is in the update method
It s running everyframe then

So when i m moving my cursor, my house is following my mouse but with this distance increasing or decreasing depending of the position of my cursor and that s annoying

i really don t get why.

 

You say that, but you did not find any helpful information doing so, meaning the advice is definitely on point. You are the one who has the code. You are the only one who can get further information about why it is doing what it is. Otherwise feel free to post a minimal working example we can copy paste and reconstruct which shows the problem. Then people, who are nice enough to do the work for you, could also debug it. Otherwise that's something only you can do

Not true at all. Does this run every frame?

Code (CSharp):

1. // Inside Update()
2. if(false){
3.     // Never runs!
4. }

No, i'm not joking. Something like this can literally happen (ideally not because you literally wrote 'false' there, but still). And that's what @Kurt-Dekker meant when he said to find out how often code is running. You posted a very minimal code example. Which is mostly out of the documentation. So that's likely not the culprit, meaning the problem is likely somewhere else in your code, or project hierarchy, where we have no information about.

 

What happens if you try using Physics.Raycast instead of terrainCollider.Raycast?

 

Following this document link
https://docs.unity3d.com/ScriptReference/TerrainCollider.html

And if you only want to detect the terrain, then use

Collider.Raycast() rather than Physics.Raycast():

or this

if ( Terrain.activeTerrain.collider.Raycast(ray, out hit, 1000f) )

 

Hello and thanks for your answer but that is actually what i am using as written in my first post

TerrainCollider terrainCollider = Terrain.activeTerrain.GetComponent<TerrainCollider>();
if (terrainCollider.Raycast(ray, out hitData, 200))

If i use Physics.Raycast, my house is flying closer and closer to my camera going from down to up and the doing it again
I suppose because it puts itself each frame on the top of its last position and going like this upper and upper until reaching the camera



Yoreki + Kurt, you are surely right but i don t know what more i could post you because there is nothing more than this in the class
buildingToCreate is intialized with a prefab at first and the terrain is already here.
So i would love to tell you more or give you more informations but i don t know how
I was just trying to follow this video

But for me doesn t do the same and i don t get why

 

here with the Physics raycast

and then the terraincollider raycast

 

Ha I know that guy, Jason Weimann.. he does great stuff.

As you noted, it looks like in the first one (Physics Raycast) the house is hitting itself again and again and placing itself higher up to the camera.

Using the terrain collider is best probably. Try replace your house with a Unity Cube Primitive and see where it ends up. If it isn't offset, then you have an offset in your house prefab. If the cube is offset as much as the house, then there's a bug, perhaps somewhere in the scaling possibly. ALL scale values should be (1,1,1) except for GameObjects that have zero children (eg. "leaves").

 

With the physics raycast youll have to set the layermask of your terrain and raycast layermask inorder for it to only cast for the terrain.

For the physics raycast vid, even in the first frame, the house was offset by a set amount. in the terrainCollider raycast vid, the raycast seems fixed aswell. best if you try what @Kurt-Dekker recommended first.

Assuming what we see of the house is the collision of the house though, this does not explain why your physics raycast would detect the house with how far the mouse was from the house collision.

 

turn off the collider on the "blueprint", very simple solution to this problem, heh
what i do with build menus like this is just take the renderer with a special transparent material to show where the building will be and when the player clicks build it just tells the game "build this building here" and the game spawns a new building there without caring what you did before (also makes it so the AI and the player use the same function to build buildings on the map)
after that if you hold shift - carry on building the same blueprint, if not clear out the "active building".

 

Thanks a lot for your help
So i tried the cube and... same problem exactly

I don t use scales, they are all at 1
I mean it s only a terrain, a camera and a cube

 

So i realised that if i put my cursor in the down left corner, then the cube is aligned to my cursor
but only there

 

Tried also but it doesn t work even if i put a layer on my terrain and in the function like this
if (Physics.Raycast(ray, out hitData, 1000, 11))
with terrain layer set a 11

 

There are other flavors of raycast you can use. For instance if there is only one collider (Say the TerrainCollider), then you can raycast ONLY against that.

Instead of Physics.Raycast (a static method that transacts against the entire Physics system), you would use Collider.Raycast, which takes a single instance of a collider and raycasts to it.

Alternately to avoid going too off-track from the tutorial, back up and go over the parts related to the collider. You clearly have a problem with one of the steps in the process.

 

Thanks so much for your help
I really think the problem was from the camera because when i used the main camera (which is in 1st person view) it works perfectly

So i decided to change a bit how to create my buildings and make it a first person view instead of doing so on the minimap. And that works.

Still i really thank you and i m a bit sad i didn t find why but i spent too much time on it, and at some point you have to decide what to do... still running or finding an other way.