Document how to work with Object3D.DEFAULT_MATRIX_AUTO_UPDATE set to false

[gewesp]

To maximize performance, three.js recommends to set matrixAutoUpdate to false for static objects.

This can be done in r3f, but it looks like then a matrix={...} argument must be provided to 3d objects instead
of position, scale etc.

Setting the global Object3D.DEFAULT_MATRIX_AUTO_UPDATE to false seems to require some extra considerations which are unclear from the docs.

Does r3f support / plan to support operation with the flag set to false?
If no:

• Document the requirement for DEFAULT_MATRIX_AUTO_UPDATE to be true.
• Document requirements for 3d object parameters when matrixAutoUpdate is set to false for individual objects.
  If yes:
• Document necessary steps to make r3f code work in that situation.

In both cases, it would be good to have a few phrases about the matrix update, e.g. under the Performance section.

[drcmda]

there's nothing r3f specific. you can use DEFAULT_MATRIX_AUTO_UPDATE, same way it's being recommended by the docs. generally all these settings work the same way in fiber as they do in vanilla, without exception.

Object3D.DEFAULT_MATRIX_AUTO_UPDATE = false
...
<mesh> // <- this mesh will not update matrices

you can also use THREE.Object3D.prototype + onUpdate which allows you to switch of matrices and, one time, update position/rot/scale anyway, see: https://codesandbox.io/s/angry-jasper-6953er?file=/src/App.js:275-299 this though would only work in fiber.

[gewesp]

Thanks for the quick reply, this my actually help us.

But isn't it a bit of a monkey patch? What if three.js decides to introduce an onUpdate() function?

Also, would it work for a mix of static / dynamic objects and other components, e.g. drei <GizmoViewport>?

Will try it out and report back. If it works, it would be nice to have the approach documented in the r3f docs.

[gewesp]

Also, would it work for a mix of static / dynamic objects and other components, e.g. drei <GizmoViewport>?

In my tests, it's breaking <GizmoViewport>.

Also, we have some (also static) objects in the scene that are created outside r3f, so I suppose they wouldn't be aware of the onUpdate().