Are there any definitive statements about how long a svf2 derivative is stored by autodesk? I would like to reuse them as cache. It could be that some svf2 are not accessed for months. Is their a way to store them by myself?
Regarding your "how long are SVF2 derivative files for supported model formats of the APS Model Derivative API available on the Autodesk APS server",
I suppose your models are uploaded to your developer-managed OSS Buckets, and you translate them to SVF2 yourself using POST /job.
Once the SVF2 translation job of a supported model format (e.g, rvt, ifc, ipt, etc) was completed and successful using POST /job, and you don't call DELETE /{urn}/manifest to delete translated files, then the translated files, called derivative files (e.g., SVF2, SVF, DWG, IFC, OBJ, etc), for the model will be available on Autodesk APS server near forever.
It doesn't follow the retention policies of the OSS Bucket, because derivative files are stored on the OSS Bucket of the Model Derivative service. After the source model files (e.g, rvt, ifc, ipt, etc) are deleted from your OSS Buckets, their derivative files won't be affected. Afterward, while you want to view the SVF2 model of your model, all you need is to pass its base64-encoded URN to the viewer. You don't need to translate the source model files to SVF2 again using the Model Derivative API (POST /job).
Furthermore,
We don't say forever because the policy changes would change this in the future, and the service would also delete the derivative files automatically if you don't access them for a long time.