the correct way to set _worldMatrix of a mesh

[yokewang]

I want to set the _worldMatrix directly instead of calling computeWorldMatrix from position/scale/rotation. (For performance issue)

But the _worldMatrix will be updated when the rendering system calls computeWorldMatrix internally.

So, I have to use below code to prevent computeWorldMatrix.

Quote

 

myMesh._worldMatrix = matrix;

(<any>myMesh)._isWorldMatrixFrozen = true;

 

But I am not sure If this is the correct way.

 

Thanks.

[RaananW]

Instead of accessing isWorldMatrixFrozen directly, you could call

myMesh.freezeWorldMatrix();

There is no setter to the world matrix (as far as I know), so technically, the only way to do this is to set it the way you do. But why not set the transformation once, have the matrix calculated and then freeze it? wouldn't it be better?

[yokewang]

Thanks RaananW, I have first tried freezeWorldMatrix, but it calls computeWorldMatrix internally. And I find computeWorldMatrix will be very slow when scaling.

https://playground.babylonjs.com/#BU5QQR#4  it's fast with out scaling. 234ms for my computer.

https://playground.babylonjs.com/#BU5QQR#3 it's very slow when scaling. 2607ms . And when size change to 30, it will be timeout.

Thanks.