dupliframes on parented object

I am trying to model a snail shell in blender from the animation of the shell “mouth” as the shell grows over time. I want a method that is very parametric and that would allow me to create non-linear change, so I thought animation and duplication from frames would be the key.
I set up a cube, which might as well be an empty, to act as a parent object for a child object, a circular polygon of the shell ‘mouth’.
-I’ve assigned YLoc and YRot animation to the cube. It acts as the axis of the snail shell growth pattern along the Y axis.
-I’ve assigned XLoc, ZRot, and X/YScale to the ‘mouth’ cross section and made the cube its parent.

Where I am running into a problem is when I select the cross section and set ‘Duplication’ to ‘Frames,’ the transformations on the parent object are not taken into account.


Is there something i can do to make this work?

eventually I also want to give the shell section an inner surface, vary the thickness of the shell, and trim the cross-section as it grows against the old shell.

okay, I’m not sure what I did, but I did something that made Duplicate > Frames take the parent’s animation into account. However I can’t repeat it. Also still looking for a way to loft the dupliframe result. Bug? Using 2.7…

So I found out about shape keys and have high hopes for them. I use the shapekey to move the section away as it also rotates around the main axis (I’ve inserted keyframes for the shapekey’s Value). Still an odd problem, Duplication> Frames doesn’t appear to take into account the shapekey keyframes, resulting in this at beginning and end of animation;


I would think duplication>frames would result in a static series.
Still need to figure out how to skin between loops, booleans, textures.
I’ve seen there’s another post on here from a guy who’s trying to write a python script to make sea shells…