Hi:
The relationship between MGRID and IE3DLIBRARY is similar to Assembly and C++.
MGRID's basic objects are vertices and polygons. You can edit them easily. You cna modify your shapes by controlling down to the vertices. IE3DLIBRAY's basic obejcts are the basic geometry shapes such as circles, rectangles, ellipses, you can easily change the dimensions while you may not be able to change its small details such as a cut on a circle. As a matter of fact, the Boolean operation in IE3DLibrary does allow you to create a cut on a cirlce easily by combining multiple objects together. The UWB antenna documented in the manual is an excellent example. There is no object as an eliptical shape inside an eliptical shape in the library. However, you can make it from two elliptical shape by digging a hole on another one. Not only that, you can even change the dimensions of the shapes in a coordinated way to achieve the tuning and optimzation. Combing with the FastEM technology implemented into IE3DLIBRARY (and MGRID), users can perform real-time EM tuning and optimization and even synthesis.
For fractal antennas, you can do a lot of things using IE3DLIBRARY. A typical fractal antenna is a one with smallest triangles inside smaller triangles and inside large triangles, .... Using MGRID to build it, you may have to build differnt triangles on different layers. Then, use some triangles to build the holes on another level after alignment. It is ok. However, you can't change the dimensions after you build the polygons. If you parameterize it on IE3DLIBRARY, you can easily change the dimensions. Not only that, you can fine tune your procedure to make sure there is no mistake is make. You can repeat the procedure again and again to test it until it is good. You don't need to worry about making a mistake in some previous step because you always can go back to fix it in IE3DLIBRARY because it is script like internally. You just need to plan ahead more than on MGRID. From our experiences, MGRID is still very useful and it can't be replaced by IE3DLIBRARY even IE3DLIBRARY is more like C++ and MGRID is more like Assembly. There are somethings you still need to use MGRID to achieve it.