When exporting from Cinema 4D R20 (“Save project for Melange”) to Unreal 4.23.0 through Datasmith (4.23.0), objects are missing in Unreal (both in “World Oultiner” and “Geometries” sub folder). After many attempts with different projects and objects hierarchy configurations in Cinema 4D, the problem seem to occur with objects further than 2 levels of hierarchy (Ex: Object; in a Null; in a Null); they simply don’t import to Unreal.
Unparenting everything seem to fix the problem, as well as re configuring the objects hierarchy to not exceed 2 levels. For the larger projects (hundreds of objects),as it is a long process to go through the whole thing and check if nothing is missing, we haven’t tested thoroughly enough to conclude that this solution completely avoids the problem (also, it is not a solution as it partially defeats the purpose of Datasmith).
Note: It doesn’t seem the have something to do with the file size, as the problem also occur with smaller files ( 9 MB).