Hi Yann, thanks for sending me that sample file.

The issue with your file is that all the surfaces in that file belong to the same IGES "level", and MoI creates 1 style for each level in the IGES file and assigns a color to that style.

The problem with your case is that although file your has everything on the same level some of the surfaces have different colors than other ones. So that means that its colorization can't be represented in MoI by only creating just a single style, MoI would need to create multiple styles in order to assign different colors. But that's not necessarily so great for preserving the structural organization because then that would break the correspondence of 1 style in MoI = 1 "level" in the IGES file.

Maybe in the future this can be resolved if it was possible in MoI to have surfaces have a color property of their own as a kind of override instead of only using the color of their style assignment. But one big reason why I haven't wanted to do that is that many polygon/rendering file formats like LWO and OBJ do not work like that - they work by having a materials list like MoI's styles list and polygons are colored according to which material they belong to instead of having their own individual properties.

So anyway, with your particular file you've got just 1 level but basically 2 materials in the file. Right now MoI chooses to preserve the 1 level and just make 1 MoI style from that, that's why you don't see the other color showing up.

- Michael