Monitor changes to scale

[negow]

Hi all,

I'm using MDagMessage::addWorldMatrixModifiedCallback() along with MatrixModifiedFlags::kScale to monitor for changes to scale and update the render representation and remesh things like this.

However as it happens, this callback fatally crashes Maya 2020, and only Maya 2020. The callback needs nothing actually inside of the function body to fail, just being present has Maya crash with a stack trace related to TBB and parallel evaluation; far beyond the reaches of my code. That said, the callback works fine in DG evaluation mode. Tested with 2018-2022, breaks in Maya 2020.3 and 2020.4.

I don't expect a solution to this - although if someone can think of one that would be great. Worst case I'd like to find an alternative. Is there another way to monitor changes to scale, that doesn't involve this callback? Ideally indirect changes too, e.g. from a parent being scaled. It can be hacky, I don't mind.

Thanks!

Ps. attaching stack trace from release build without debug symbols.

The crash happens when my custom node is parented to a group which is driven by a parent constraint.

[cheng_xi_li]

Hi,

I tried to reproduce this issue and I can’t reproduce it.

Could you send us a working sample for reproducing it?

Yours,

Li 

[negow]

Hi Li, thanks for looking into this. I don't have a reproducible at this time, I was hoping there was an alternative method such that I could sidestep having to put a reproducible together as it would take time to isolate the problem. I'll give the community a few more days to stumble on this problem and offer some suggestions, and if that fails I'll make a working sample for you.

The crash happens consistently in two of my scenes in 2020, but both are of varying complexity and simpler cases do not cause a crash. It's the worst kind of bug.