MCreator issue tracker has been migrated to GitHub.
Existing tickets have been migrated to GitHub. Please open new tickets on the GitHub tracker instead. If you do not have a GitHub account, all feature requests and bug reports from forums are still considered and checked by the maintainers.
OBJ support is very limited and added by Forge, MC itself does not support OBJ models. There are many known and unknown limitations. This page might help: https://mcreator.net/wiki/custom-obj-models-blocks-and-items
But usually you would want to use JSON models instead.