PolyMass - (free)

Product Details:

PolyMass is a Cinema 4D Expression Tag plugin originally based on some COFFEE code from Darter (David Wickenden), found in this thread.

It parses a user-supplied Vertex Map tag and sets up a user-supplied Polygon Selection tag based on the weights from the Vertex Map tag.

There are also controls to set a Weight Threshold - that determines the amount of weight (0-100%) that should be looked for, as well as a Poly Vert Threshold - that determines how many of the vertices of the polygon (0-4) need to meet that Weight threshold in order for the polygon to be selected.

New in v1.1:
There is now an option to map the user-supplied Polygon Selection tag to the user-supplied Vertex Map tag.

New in v1.2:
Added code to swap out the tag's icon, depending on which map mode is active.

See the included ReadMe.txt file for additional details.

The plugin is being distributed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License and includes Visual Studio 2005 C++ source code and project file. The included (compiled) plugin is built for the PC (32 & 64bit) and Cinema 4D R12, but the code will also compile with the R13 SDK without changes. Update: David Wickenden has provided a Mac build which is now included (along with his XCode project file) in the archive - thanks David!

The plugin is is available from the downloads section (look in the 'Additional Cinema 4D plugins (free)' category). Both the PC (32 and 64bit) and Mac (Universal binary - thanks to David Wickenden) plugins are included in the archive.
This plugin is is available Free of charge, but as usual, donations are always welcome .

...every little bit helps and is greatly appreciated (the plugin is not intentionally crippled in any way, your participation is purely voluntary) - Thanks!