HI. I am using Adobe Acrobat Pro 2020 and Adobe Reader DC.
I think there is security bug at Adobe Reader DC when handling 3d-pdf files.

The problem is enabling 3d measurement tools at Adobe Reader DC with secured 3d-pdf files made by Adobe Acrobat Pro 2020.
I contacted to region customer service about this problem and received this function is intended option.

Customer center said that you’d better to contact bug report if you want to know about further information.

I should have not have bought Adobe Acrobat Pro 2020 bundle if enabling 3d measurement tools for secured 3d-pdf files.
I want to keep Adobe Reader DC from enabling 3d measurement tool when opening secured 3d pdf files have no permission.