The CBV (constant buffer view) size is required to be 256-byte aligned. (Cref.: https://docs.microsoft.com/en-us/windows/win32/direct3d12/creating-descriptors​ ).

• Should the associated ID3D12Resource have a Width equal to that same size or may it be smaller (the additional padding of the CBV won't be accessed/used in the shaders anyway)?
• Are there constraints for the IBV (index buffer view) and VBV (vertex buffer view) sizes as well?