transfer between Catia and 3dsmax

Hello,

I’m trying to transfer a project between Catia and 3dsmax, using a .igs format, but it’s not perfect. When I import it on 3ds max, it appears that the upper surfaces are transparent.
Do you have any advice, if you’ve already done that.
Thanks

Jim

I always import mesh. Using say NuGraf or PolyTrans export a detailed mesh. Max and IGES have never worked for me.