I don't know if this fits with your description of a stack : what I meant is not only the "stackable" nature of the modifiers, but also and more importantly the non-linear, "browsable" aspect of their connections.
I mean, I really love and rely a lot on Max's ability to let me go back the very lower layer of a modifiers stack (say, Editpoly stage), edit it at will (removing faces, pulling/pushing vertices, welding edges) and then go back all the way up and see the consequences of the changes through the upper levels of modifiers. And even, see all that moving and updating in realtime thanks to the Show End Result button.
This supposes that the modifiers stacked on top are smart enough to be either "per component" or "per object" depending on what is currently active below them at the time they are applied - in order to not rely too much on vertex numbers (since this order is modified when deleting faces, merging edges, you name it).
In my experience Max is fantastic for that and extremely flexible ; on the other hand even tho Maya seems to have a similar structure (even more complex actually since its node based and can branch in more complex ways) the downside is that everything in Maya seems to based on component manipulation, making it impossible to edit the lower layers of the stack/node graph without breaking the end result after reconnecting the node.
(Try that on a simple extrude of a 3*3 grid plane : i am pretty sure that if a face is removed, then the extrude node reconnected, the result is messed up)
That's why I thought that coding a good stack system is huge task (Max has it, Maya somehow has it but the history is too polluted and sadly seems component-restricted, Silo users have been asking for it for a long time and it never saw it happen...)
Fascinating stuff really!
Hope to see all that in kHed one day!!!
Last edited by pior; 03-13-2009 at 03:35 AM..