@TomaszJarmuszczak wrote:
The plate will be 3D printed from metal.
I have the paid version of Fusion.
I might change my approach. I converted it to solid because it's easier to use Fusion's 3D modeling tools, such as slicing.
The question isn't necessarily whether or not "it" should be convert it to a solid. The question is more how that conversion is done.
With the paid version you have access to the "organic" conversion.
That will allow you to create a plate that will very closely follow the 3D scan.
That will require some preparation of the mesh before you do the conversion.
First I'd separate the approximate area of the original mesh that will contain the plate.
Then I'd use the organic conversion to create a surface model of that area.
Then I would use the solid modeling tools to trim that surface to size and then thicken that surface.
Thickening can be a problem due to too tight radii in the converted surface, but for a 3D printed object, we don't need consistent thickness, so that can be worked around easily.
If precision isn't needed the method @MichaelT_123 suggested is perfectly viable , but I would still recommend working with the original mesh, not a reduced version.