How to make nodes non-storable (so don't save)?

[jade1]

Hi,
I've been searching for a way to make mesh / transform nodes non-storable (non-writable), so that when you save the scene, these nodes won't save out.
It's possible to do this for attributes, but I can't find anything relating to making DAG nodes non-writable. There are ways to roughly emulate this functionality (script nodes to delete these temporary objects when the scene is re-loaded), but I'm just wondering if anyone knows of a way to stop the data ever getting saved out..
I've tried attaching nodes to Maya's internal non-writable nodes (as indicated by isDefaultNode() method - such as groundPlane_transform), but this just causes a "Save Failed" error message when you try and save the scene .
I'm writing a particle system plugin, so like Maya's native particles I don't want the particles themselves saved out with the scene.. but I don't want to use Maya's particles because they don't offer all the visual functionality I require..

If anyone has any ideas I'd love to hear them, thanks,
Jade.

[joojaa]

A scriipt node that deletes them before save? Or a mel event that does the same.

[jade1]

Thanks Joojaa - I had considered that, and it's possible I'll end up going with that approach, provided I can find a pre-save event hook to perform this function. I'm just not sure the artists using the plugin will like that solution . Ideally they could save their work without the particles disappearing on them, but it's something they might to have to live with.

[rob-bateman]

in the API there is MSceneMessage :: kBeforeSave, MSceneMessage :: kAfterSave if that's of any use. I'd be tempted to do a joojaa said, just delete them using an MDagModifier from the before save func, then use the after save func to undo the modifier.

[jade1]

Thanks Rob, hadn't thought of doing the undo afterwards . btw found your web pages very useful, having only recently started on this (my first) Maya plugin