Unity3d Is there something like Mesh Collider for 2D objects? - unity3d

Im making simple 2D game, I designed the "way" the player going through in the game.
If the player touches the wall the game is over, so I must detect collisions.
At first I created the walls from sprites, but then I realized there is no 2D collider that suit himself to the shape of the sprit(it was to difficult to create the collider manually from a lot of smaller polygon and circle colliders), so I made all the walls that builds the "way" 3D objects(.dae files with z=0.001), and added them the mash collider which suits himself to the 3D object. I changed my player to be 3D as well so the collisions types will match.
It worked, but I'm sure the same game can work by much better performance with the same resources if all the game objects were 2D.
How can it be that there if a collider that suits himself to a 3D object but there is none for 2D?
Maybe I miss something?

At my first attempt I didn't export the sprite correctly so the polygon collider didn't recognized the shape of my sprite.
I export the sprite as JPEG, when I export it as .png it worked like a charm, just added the Polygon Collider and it match to my sprite shape perfectly, thanks!

Related

Specify walkable area in Unity 2D

I want to limit the area where my player can walk. In this case only on red segments.
And I want to use 2D sprites as background images not 3D models. But my main player would be in 3D
Can I use NavMesh here? Or should it be done with Tilemap? Or should I place some 3D objects above it?
here is another scene that I would like to understand how to build
You can try adding invisible colliders attached to an empty gameobject to prevent your character from walking into certain areas.

Blender to Unity: Add Custom Collider to A Low Poly Style Terrain

I have created a low poly terrain object from Blender using a Plane, displaced and decimated it. I then exported it to Unity as an FBX object. As what I expected, my player simply falls through it since it has no colliders on. I could place a Box Collider on the object, but seeing it is a low poly style terrain with lots of bumps, it'll be pretty awkward to have my player walk straightly even if the ground is slightly raised. Even so, there are mountain areas in my terrain object and box colliders would totally be out of the question.
I was thinking of using the Mesh Collider in Unity. I tried experimenting with it but failed. There are also no clear tutorials online on the said situation. How can I add a custom collider to this terrain so the player can walk to it, plus without using the hastly Box Collider.
Here is my terrain object in Blender:
As you can see, putting a box collider is totally impossible.
You can make individual Sphere, Capsule and Box Colliders, hide their Mesh Renderers and then rotate, scale and place them to make something similar to your mesh. However, Mesh Colliders should be your best option, after adding a mesh collider to your mesh, make sure the convex option is NOT checked and also make sure to select the same mesh that the GameObject is using from the Mesh field in the Mesh Collider component.
Alternatively, if you want your collider to be simpler than your actual mesh, you could make a simpler mesh (either with an external program or by downloading the ProBuilder package in Unity), overlay that mesh with the terrain you have, give it a Mesh Collider and then hide its Mesh Renderer component.
I don't exactly understand what you meant by "I tried experimenting with it but failed." Did your character keep falling through? Did the character get stuck? Was the mesh collider generated in an incorrect way? I would be able to help you better if you can give me a detailed explanation.

Why the player is walking through objects in scene?

Instead walking on the ground he walk through it same for the ship and debris the other objects. He stay on the ground on the terrain but all the other objects in the scene he walk through it.
In the past i added Mesh Collider to the ship sapceship and checked the Convex turned the Convex on so it worked fine. but now i tried to add Mesh Collider almost to everything in the scene and it didn't change anything.
The scene is not my own but there is nothing speical i think. A terrain camera and objects. I added the ThirdPersonController.
Maybe there is a way to solve it making a new script in c# ? So far i could not find solution.
Make sure the collider of the Player is big enought to hold the model. And also that the terrain collider is adjusted to the terrain.
Try to change Center(Y) value of CapsulCollider

Unity 4.5 Mesh Collider Not Interacting with Circle or Box Collider 2D

I am new to unity and I am working on a 2D game. Currently, I am having trouble getting two colliders to interact when one of them is a mesh collider and the other is a box or circle collider. I was originally working to get the Unity Sample Assets 2D character to interact with a mesh terrain. When I "played" the game, the circle collider attached to the legs of the character was falling through the mesh terrain. I have simplified the problem and created two cubes:
One cube I upload and keep the 2d box collider and add a rigid body to
The second cube I delete the 2d box collider and add a mesh collider
I place the second cube under the first cube and hit "play". The top cube falls through the bottom box. When I replace the bottom cube's mesh collider with a box collider and hit "play" it correctly collides and stops on the box. I'm guessing I'm making the same mistake in this simplified example as I am in the more complicated 2D Character scenario. Do you have any suggestions of what I am doing wrong? I have tried making the mesh collider convex (although I believe this should only be necessary between two mesh colliders?). I have also ensured that the z position is the same as well as the layers of the two objects.
You cannot collide a 3D object against a 2D.
void OnCollisionEnter2D(Collision2D coll)
{
// Code here is clueless about 3D.
}
API Reference.
Sent when an incoming collider makes contact with this object's
collider (2D physics only).
You could cheat a little. Before Unity had 2D colliders what people would do is create a very thin box collider3D, which in your case should work.

Can a Polygon Collider 2D work with a Mesh Collider in Unity?

EDIT: This is now a rather simple question. I have a 2D sprite that really needs the precision of a polygonal hitbox. The 2D, tile-based world around it uses a tile Mesh for efficiency reasons, and thus has a Mesh Collider.
Before, the tiles in the world were each GameObjects with Box Colliders and Rigidbody 2D's, and the ship and the tiles collided just fine. Now that I am using a Mesh Collider, however, they cannot collide. (I have read that this is because one is 2D and one is 3D.) So what should I do to get collisions (preferably with rigidbody physics) between a polygonal ship and a 2D tile mesh? [end edit]
In a 2D, tile-based, procedurally-generated, chunk-based exploration game (in Unity 4.5), I have a player ship which uses a Rigidbody 2D and a Polygon Collider 2D for collision detection.
This worked fine back when I used a Rigidbody 2D / Box Collider 2D for world tiles. However, this is horribly slow, so I replaced the discrete blocks with a tile mesh, using a Mesh Collider and other associated paraphernalia.
The problem is: I simply cannot get collision detection to work. I have tiles on the x-y plane, and the collision mesh (I can see it in the Scene View, so I know it works) consists of four rectangles perpendicular to the tile. (If you can't visualize this, I don't blame you. See here.)
What have I looked at so far? Well, I verified that the (2D) ship actually passes through the collision boxes in the Scene View. Also, neither of the colliders "Is Trigger".Since there seems to be no official documentation on how to actually use meshes (is there? Where?), I can't find out whether Mesh Colliders and Polygon Colliders actually can interact. Because one is 2D and one is 3D, does this not work? If so, then what should I do instead? I tried using a Box Collider [3D] for the ship, but this didn't work either. I could have potentially made a mistake here, though.
Am I supposed to handle the collision manually (with the OnCollisionEntered [or something] method)? Before, the rigidbody2D objects handled everything automatically. Otherwise, is there any other possible reason the collision might not work?
Well, I'm quite disappointed there seems to be no built-in way to do this in Unity. My solution was to attach a GameObject to the player that would read the block data from the world and create (pooled, of course) real but invisible "collider blocks" with Box Colliders 2D in a small area around the player, such that the player could collide with blocks near them. It works great, and I also implemented an algorithm to spawn rectangular collider blocks over groups of blocks; this eliminates the "ghost pixel" bug in the 2D physics engine.
Uni2D plugin (https://www.assetstore.unity3d.com/en/#!/content/3826) automatically creates 3d colliders (as a group of mesh colliders) from any 2 texture with transparency. A bit expensive but works.