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Change vertex position not working?
There are other things going on in the code but this part doesnt seem to be working. I am trying to get the vertex positions, rotate the object, then tell it to have its verts where it was previously, even though the rotation has been changed.
verts = theMesh.vertices;
theMesh.transform.localRotation = Quaternion.Euler(0,0,0);
theMesh.vertices= verts;
I guess the verts variable holds a reference to the vertices array, not an instanced copy.
@cherno I had a feeling. I tried to make another array and copy the copy, but that doesn't work. How can I get a clean copy? Do I have to make a copy of the mesh?
Answer by Bunny83 · May 05, 2016 at 03:44 AM
Vertices are defined in local space. So the rotation of the object is irrelevant for the vertex data.
What you have to do is:
transform your vertices into worldspace before you rotate your object
rotate your object
transform the vertices back into local space
Example:
verts = theMesh.vertices;
for (int i = 0; i < verts.Length; i++)
verts[i] = theMesh.transform.TransformPoint(verts[i]);
theMesh.transform.localRotation = Quaternion.Euler(0,0,0);
for (int i = 0; i < verts.Length; i++)
verts[i] = theMesh.transform.InverseTransformPoint(verts[i]);
theMesh.vertices = verts;
Note: your code seems a bit strange. What exactly is "theMesh"? If it's the actual Mesh instance, you can't get a "transform" from it since it's just a Mesh and not a GameObject. If it's actually a GameObject or MeshFilter you would have to use the mesh property to access the mesh.
Thank you. Will try this. Yeh the $$anonymous$$esh is the meshfilter mesh.
Answer by Cherno · May 05, 2016 at 01:31 AM
I use this handy script I found online in all my projects to copy any kind of data.
using System;
using System.Reflection;//for copying objects
using System.Linq;//for string[].Contains()
using UnityEngine;//for print
public class CopyData {
/// <summary>
/// Copies the data of one object to another. The target object gets properties of the first.
/// Any matching properties (by name) are written to the target.
/// </summary>
/// <param name="source">The source object to copy from</param>
/// <param name="target">The target object to copy to</param>
public static void CopyObjectData(object source, object target)
{
CopyObjectData(source, target, String.Empty, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
}
/// <summary>
/// Copies the data of one object to another. The target object gets properties of the first.
/// Any matching properties (by name) are written to the target.
/// </summary>
/// <param name="source">The source object to copy from</param>
/// <param name="target">The target object to copy to</param>
/// <param name="excludedProperties">A comma delimited list of properties that should not be copied</param>
/// <param name="memberAccess">Reflection binding access</param>
public static void CopyObjectData(object source, object target, string excludedProperties, BindingFlags memberAccess)
{
string[] excluded = null;
if (!string.IsNullOrEmpty(excludedProperties))
{
excluded = excludedProperties.Split(new char[1] { ',' }, StringSplitOptions.RemoveEmptyEntries);
}
MemberInfo[] miT = target.GetType().GetMembers(memberAccess);
foreach (MemberInfo Field in miT)
{
string name = Field.Name;
// Skip over excluded properties
if (string.IsNullOrEmpty(excludedProperties) == false
&& excluded.Contains(name))
{
continue;
}
if (Field.MemberType == MemberTypes.Field)
{
FieldInfo sourcefield = source.GetType().GetField(name);
if (sourcefield == null) { continue; }
object SourceValue = sourcefield.GetValue(source);
((FieldInfo)Field).SetValue(target, SourceValue);
}
else if (Field.MemberType == MemberTypes.Property)
{
PropertyInfo piTarget = Field as PropertyInfo;
PropertyInfo sourceField = source.GetType().GetProperty(name, memberAccess);
if (sourceField == null) { continue; }
if (piTarget.CanWrite && sourceField.CanRead)
{
object targetValue = piTarget.GetValue(target, null);
object sourceValue = sourceField.GetValue(source, null);
if (sourceValue == null) { continue; }
if (sourceField.PropertyType.IsArray
&& piTarget.PropertyType.IsArray
&& sourceValue != null )
{
CopyArray(source, target, memberAccess, piTarget, sourceField, sourceValue);
}
else
{
CopySingleData(source, target, memberAccess, piTarget, sourceField, targetValue, sourceValue);
}
}
}
}
}
private static void CopySingleData(object source, object target, BindingFlags memberAccess, PropertyInfo piTarget, PropertyInfo sourceField, object targetValue, object sourceValue)
{
//instantiate target if needed
if (targetValue == null
&& piTarget.PropertyType.IsValueType == false
&& piTarget.PropertyType != typeof(string))
{
if (piTarget.PropertyType.IsArray)
{
targetValue = Activator.CreateInstance(piTarget.PropertyType.GetElementType());
}
else
{
targetValue = Activator.CreateInstance(piTarget.PropertyType);
}
}
if (piTarget.PropertyType.IsValueType == false
&& piTarget.PropertyType != typeof(string))
{
CopyObjectData(sourceValue, targetValue, "", memberAccess);
piTarget.SetValue(target, targetValue, null);
}
else
{
if (piTarget.PropertyType.FullName == sourceField.PropertyType.FullName)
{
object tempSourceValue = sourceField.GetValue(source, null);
piTarget.SetValue(target, tempSourceValue, null);
}
else
{
CopyObjectData(piTarget, target, "", memberAccess);
}
}
}
private static void CopyArray(object source, object target, BindingFlags memberAccess, PropertyInfo piTarget, PropertyInfo sourceField, object sourceValue)
{
int sourceLength = (int)sourceValue.GetType().InvokeMember("Length", BindingFlags.GetProperty, null, sourceValue, null);
Array targetArray = Array.CreateInstance(piTarget.PropertyType.GetElementType(), sourceLength);
Array array = (Array)sourceField.GetValue(source, null);
for (int i = 0; i < array.Length; i++)
{
object o = array.GetValue(i);
object tempTarget = Activator.CreateInstance(piTarget.PropertyType.GetElementType());
CopyObjectData(o, tempTarget, "", memberAccess);
targetArray.SetValue(tempTarget, i);
}
piTarget.SetValue(target, targetArray, null);
}
}
Uhm, that's pretty pointless ^^. Unity already returns a copy of the vertex array. The problem is that vertex position are defined in local space, not in worldspace. So the actual object rotation is applied in the shader via the model matrix which contains the position, rotation and scale of the object. When you rotate or move an object, it's vertex data won't change at all.