http://www.clayworks3d.com/
http://cs-svr1.swan.ac.uk/~cstim/clay/downloads/winclay.zip

Version 3.0 is a complete departure from the older versions of ClayWorks, which are still available for download from this site, and has been in development for two years. 
The new version features both software and hardware rendering, an intuitive interface and support for parametric, polygonal, spline and metaball primatives.   A lot of work has gone into making ClayWorks a high quality yet low cost solution for your 3d modeling needs. There is still a lot of work to do but there will be a viewer application and then a full beta test released in the comming months.
ClayWorks sports it's own, highly flexible, custom interface which can be altered to your taste. 

This interface is consistant across the various platforms that ClayWorks will appear on but it is a windowed application and makes use of the services offered by each platform, such as the clipboard and drag & drop support.
The interface has a solid, speedy feel and lacks the annoying flickering and slugish update problems that have long plagued applications in Microsoft Windows. The attention to detail shown in the ClayWorks interface is representative of the way this program will be a superior product.