Toolpath Efficency WRT shadows & defining stock

[jzabel]

In short, my questions are:
1. Is there any way for Mastercam to understand and remember what it has shadowed? and
2. Is there any way for Mastercam to use the shape of the stock to write a more efficient toolpath?

Background:
I use Mastercam v9 and X to write toolpaths for two large, custom built, 3-axis machines and a MotionMaster/Fagor 5-axis. I primarily cut urethane and EPS foam as plugs or molds for sculpture and architectural patterns.

Problem:
The issue I'm having is with cutting a complex shape from an STL (picture a head for example) using 3 axes and then returning from another angle to remove the shadows (like behind the ears, under the chin, etc). The technique I've been using is to write a pair of 3-axis parallel toolpaths which rough and finish normally from the Top plane. Then I write subsequent parallel toolpaths which finish from, say, the Front, Back, and sides. These subsequent toolpaths re-finish the entire part, including the shadows AND what has already been finished. To improve the efficency of this I can manually define containment boundaries from the sides which limit the toolpath to what I predict to be shadowed areas. In simple situations this works well, but I'm looking for something smarter and more effecient, especially for very complex parts where predicting the shadows isn't so easy.

Failed Solutions:
Ideally I'd like to be able to have Mastercam *know* where the shadows are from the previous cut, although I havn't been able to find anything that works that way. The closest I can find is the Restmill operation, but that seems to work to remove areas which couldn't be cut by a larger tool, not shadows. The next closest I can get is by saving the STL once it's been verified and using that as stock for the subsequent operations. The problem I'm having here is that Mastercam doesn't seem to regard the shape of the stock when writing toolpaths. I only see it being used when it verifies. Besides, saving the STL doesn't actually save any information about where the shadows are.

Hopefully I'm not missing something obvious like a checkbox somewhere but I've poured over this without much progress. Any ideas or advice would be great ...

Cheers
Josh

[chipproducer]

Sorry, but I have found no magic trick for what you want to do.
You could try to use WCS to change your top plane to the side for example, and then use the new HST toolpaths with restmill options. The new HPT toolpaths are great.
Haven't tried this yet (still doing it the old way that I am used to) so I don't know if it will work, but is is worth a try.