get matrix of local transform

hi all!
I wish obtain the matrix generated with transform.localPosition and transform.localRotation..
how can I do? if I use the transform.worldToLocalMatrix is not correct, 'cause took the parent global position, and I don't want it!

thanks

 

transform.localToWorldMatrix.inverse perhaps?

 

nope...

 

Perhaps you could describe in more detail what you need?

 

I have a mesh into my gameobject, and I need to cycle to the vertex, and I need the position relative to the parent (not to the world), 'cause this mesh may be scaled, rotated or translated

thanks @blizzy

 

Create a new matrix with Matrix4x4.TRS

 

thanks @steego !! it works!!!

 

Another way to "remove" one transformation matrix from another is to multiply its inverse with your original matrix.

local_matrix = transform.parent.localToWorldMatrix.inverse * transform.localToWorldMatrix;

I've found the functions for creating new matrices from position, rotation and scaling to be somewhat unreliable/work somewhat unexpectedly for flipped objects. I'm also a SketchUp plugin developer so I've lived a few years now in Matrix Land .

 

This is a life saver! Thanks!

 

I have never seen this. Note that we talk specifically about using the localPosition, localRotation and localScale. You can not use the position, rotation and lossyScale because the scale will be the actual issue here. Using those 3 would somewhat work for transformations that do not contain any shearing. However if you need the localToWorld matrix, you would just use the localToWorld property anyways ^^.

The reason why using the lossyScale does not work is that the TRS method can only construct a 3x4 matrix from the given information. If you have a shear going on you usually need the 4th row of the matrix. This can not be represented by a position, rotation and scale alone.

However for a local matrix, this should always work:

Code (CSharp):

1. var local_matrix = Matrix4x4.TRS(t.localPosition, t.localRotation, t.localScale);

Of course

t

is the Transform you're interested in.

For everyone reading this, the local matrix is the matrix that brings you from object / local space into parent space. Of course the approach that eneroth3 took is a general way to convert from one space to another. by meeting at a common space. Note that there's no reason to do

localToWorldMatrix.inverse

since the Transform component provides the inverse already as

worldToLocalMatrix

.