Hello, Welcome to Microsoft Q&A,
Please try to use some third-party applications to convert and/or optimize your models. For the format about 3D model assets, it is recommended to use .glb file format and refer to this general guidance that includes triangle counts: https://learn.microsoft.com/en-us/dynamics365/mixed-reality/import-tool/optimize-models
----
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.