How I finally solved turning a scanned mesh into usable CAD - steps that actually worked

I used a similar method when I was modeling a bracket for a piece of equipment and found that the placement of the coordinate system is everything. I always start by importing the mesh and aligning the major reference planes, usally the XY or XZ plane, to match the real-world flat surface of the object. This gives you a proper starting point for your sketch instead of having to guess where the origin is in the messy scan data. I found that even after I nudged my lofted shape to look perfect against the reference mesh, I still had to dial in the clearance for the mounting bolts. If I rely solely on the visual fit, I always end up with parts that are a hair too tight for the holes. I usually design the mounting holes with about 0.5 millimeters of extra space to make assembly smooth, even if the scan suggests they are tighter. It prevents me from having to print five versions just to get the fit right.

Using the alignment tools in Fusion 360 helped me constrain the basic solid geometry before moving on to the complex curves. It made the entire process feel much more stable than just hand nudging everything around.

Back before we had scans at all I'd do this with a contour gauge and a set of calipers, tracing profiles onto paper and building the model from those. Honestly the workflow is the same, just faster now. One thing I'd add is to section cut the mesh at a few heights and check your solid against those, not just the outer view. A part can look dead on from the outside and still be a couple mm fat in the middle, wich you won't catch untill the test print sits proud somewhere.

Yeah the hole spacing thing is real, I went through the same pain on a knob for my grill. Even after I had the outer shape matching the mesh, the bolt pattern kept coming out tight. What helped me was printing just a flat disc with the hole pattern on it first, before wasting time on the full part. A 10 minute print told me everything and I widened the holes once and never touched them again. Also agree on keeping the mesh as dumb reference only, I always set it to like half transparency so I can see my solid through it while checking the fit.

I'm brand new here so sorry if this is a dumb question, but my situation is a bit diffrent. I don't have a scan of my part at all, just a broken knob off an old appliance. I've been taking measurements with a ruler and eyeballing photos from a few angles. Does the same idea apply, where I sketch out the simple stuff fresh instead of trying to copy every little curve I see? The rounded grip part is what's stumping me. I figured I'd just get the diameter close and smooth it from there, but it keeps looking lumpy compared to the original.

Update: I tried lining up the main reference planes like you suggested in the first reply and that really helped get the basic orientation right. The large sections now sit where they should relative to the ground. However, the tricky parts where the surface curves inward still look a little off when compared to the actual object. How should I go about refining those small overlaps without messing up the overall structure?