Hi there...
i dont know if MED is capable of importing obj, cob or lwo-files.
But it can read 3ds...
If u open MED u have to go here: File/Import/From 3ds
The error u get (Too many Skins) is because u have multiple Textures on your exported mesh...
to get a workaround, u have to assign just a single texture, save it, export/import again.
ok... when u finally got the mesh into MED. Now u need to re-apply the Texture
to the mesh...
do this in the skin editor (in MED View/Skins)
then go File/Import/Skin Image and choose your Texture
the Texture-File can be a bmp, pcx, tga, dds (i'm always using tga's because it can use alpha-channels to do transparency and other cool stuff)
and the Texture-Size should always be 32*32, 64*64, 128*128, 256*256, 512*512, 1024*1024, 2048*2048, (4096*4096... will use alot of memory... i wouldnt go bigger than this)
u can also swap the values like this: 128*512, 1024*64, 512*256.... these are valid texture sizes.
to your last question about particles, i never did particles myself, so i cant give a answer on that.
cheers
sinnlos
PS: there are quite a few threads about importing different file formats into MED in this forum... maybe they are helpful to u.