Although Adrian Woods has an interesting post about how to add attachpoints to your X file, it still took me most of the evening to get things working. First I probably picked a wrong effect that does not work for scenery, but I also forgot to add the mesh to the X file frame of the attachpoint. Although that mesh is not put into the MDL when compiling with XtoMDL, it still has to be present in the X file.
But after having learned that, I could attach a nice firework show to my object converted with ModelConverterX. Now that this test is working, I can continue adding the attachpoint functionality and attach useful effects (for lights for example). But that is something I will continue working on later this week.
SceneryDesign.org
One of the most important features still missing in ModelConverterX is the ability to read in API macros that use lines instead of polygons. I have started working on a solution for this now. Those lines will be read in and then transformed into a 3D object. It is like you extra a certain shape along the line to get a 3D version. I will use a simple circle for the shape to extrude with, where the radius and number of vertices are an option the user can specify. By setting the number of vertices to 3 you would get a triangle to extrude, which costs the least polygons of course.