How to reverse engineer 3d scan of endcap ... like a revolve loft would be great

[nkloski]

Hi there!  I am trying to reverse engineer a 3D scan of what I thought was a simple shape.  The endcap of this shape is problematic, though.  One side has about a 2mm fillet,. and the other has about a 5.3mm fillet, but the "top" of the cap does not match the combined 5.3/2 variable fillet radius, and is more sloped.  So, I am thinking more advanced techniques are required.  The "side" view below is not the full story, since the slope is different on the 2mm side than it is on the 5.3mm one.

What would be great would be to use a "revolve loft" sharing the same vertical origin centerline line, but radiating out...but that tool does not exist.  Any ideas on how to create this shape?  The "red" part is what I have already created.  Thank you for any advice!

End 3Quarters viewEnd side viewEnd Top viewEnd end view

[jeff_strater · Accepted solution]

I thought someone would jump on this, but since that didn't happen, I gave it a try.  The result is not perfect, but maybe gives you some ideas.  I would use loft.  I had a bit of trouble using Mesh Section here, because the mesh in the areas where I needed a section is kind of messy.  So, I ended up doing spline fitting by eye.  Here's a step by step view of what I did (recording a screencast would take too long).

I started out trying to create a mesh section along the bottom, but the mesh flattens out there.  So, I generated one a bit higher up.  That turned out to be of limited use, but here it is anyway:

Then, I created a workplane and a sketch coincident with the bottom of the red part, and just fitted a spline there by eye.  Important step is to use Project->Intersect with the existing geometry, to assure that things meet precisely:

Next, I created another mostly useless mesh section lengthwise along the part, which will become a rail.  Then, did another manual curve fitting (again using Intersect to assure connectivity):

and then did a surface Loft to build the surface, using 2 profiles + 1 rail:

Then, added a patch at the bottom:

then, deleted the end face of the existing red solid, and stitched the whole thing back together:

as you can see here, the new loft sticks out a bit from the mesh.  If that is OK, great.  Otherwise, you might have to add more rails to get a better approximation of the mesh.

my model is attached.  Hope this sends you in the approximate right direction.

[nkloski]

Wow, thank you Jeff!!  I guess my "revolve loft" idea really was that...using the bottom edge of the existing form as the common edge and using the intersected rail as the guiderail.  This is really really helpful.  I could use more mesh sections as rails if I needed it to be more accurate.  Really, how can I better thank you? ???