Brent wrote:
I have cedar clapboards on my house with the rough side facing out. We
are trying to understand the best way to scrape/sand the old paint off
without having to sand it smooth and remove the rough look. ...

Unless it's peeling, my suggestion is to simply to power wash
(carefully to not gouge the soft material) and then perhaps use a wire
brush or other stiff bristle to remove any loose paint then repaint.
Now you understand a prime reason not to paint over rough-sawn
material...