Question by jisase · 4 days ago · c#mesh meshes deformation mesh vertices

How to deform a mesh at runtime?

Hi, I am trying to modify a mesh at run time based on the mouse position. It is the first time that I work with meshes and something is happening to me that I don't understand, if someone can help me I would appreciate it very much.

this is my code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class MeshController : MonoBehaviour
 {
     [Header("CUSTOM VALUES")]
     public float radius = 2f;
     public float deformationStrength = 2f;
     public float smoothingFactor = 2f;
 
     [Header("REFRENCES")]
     public GameObject brush;
     public Camera cam;
 
     private Mesh mesh;
     private Vector3[] verticies, modifiedVerts;
 
     private void Start()
     {
         if(cam == null) cam = Camera.main;
         if (brush == null) brush = GameObject.FindGameObjectWithTag("Brush");
 
         mesh = GetComponentInChildren<MeshFilter>().mesh;
         verticies = mesh.vertices;
         modifiedVerts = mesh.vertices;
     }
 
     private void Update()
     {
         RaycastHit hit;
         Ray ray = cam.ScreenPointToRay(Input.mousePosition);
 
         if (Physics.Raycast(ray, out hit, Mathf.Infinity))
         {
             for (int v = 0; v < modifiedVerts.Length; v++)
             {
                 Vector3 distance = modifiedVerts[v] - hit.point;
 
                 Debug.DrawRay(modifiedVerts[v], hit.point, Color.red);
 
                 float force = deformationStrength / (1f + hit.point.sqrMagnitude);
 
                 if (distance.sqrMagnitude < radius)
                 {
                     if (Input.GetMouseButton(0))
                     {
                         modifiedVerts[v] += (Vector3.up * force) / smoothingFactor;
                     }
                     else if (Input.GetMouseButton(1))
                     {
                         modifiedVerts[v] += (Vector3.down * force) / smoothingFactor;
                     }
                 }
             }
 
             brush.transform.position = hit.point;
         }
 
         RecalculateMesh();
     }
 
     void RecalculateMesh()
     {
         mesh.vertices = modifiedVerts;
         GetComponentInChildren<MeshCollider>().sharedMesh = mesh;
         mesh.RecalculateNormals();
     }
 
     private void OnDrawGizmosSelected()
     {
         Gizmos.color = Color.yellow;
         Gizmos.DrawWireSphere(brush.transform.position, radius);       
     }
 }

When I run it, the ray that I draw inside the for indicates me that it is only returning me a vertex and only when I place myself over it is that the mesh is modified and I should be able to modify each vertex of the mesh. What am I doing wrong?

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