Morphing / Reshaping a part

Hello All,

I align 3D scans of car parts for my job which is where and how I have learned to use this software.

I have one problem though with a project I am currently working on, that my team and I decided to reach out to you for help with.

Before the car gets torn down, we do a 3D reference scan of the car inside and out,
that way later when everything is taken apart we can fully scan the parts and align them back to
the original location.

As you may know, during the reference scan some parts are only available side scanned, like the outside of the bumper.
If I am working on one of the bumpers, the reference scan will only show the outer part, and later on when the bumper
is removed we can fully scan it and get the inside of it.
However, 98% of the time the bumper and other parts flex and change shapes which makes it difficult to align.

I was wondering if there was a way on Blender to morph a part or in other words have the fully scanned part that flexed durning full scanning reshape
itself to match the original shape?

Below I will attach 2 STL files for a similar problem.

The reference file needs NO changes and it must stay the same shape,
The 2nd file is the one that I want to match and align completely with the reference file.
If you know a way to do this, I would appreciate the support.

I used many other methods like SHIFT + W, and Sculpting method, ect. but none of them seem to work right.

I am sorry if this was hard to understand, if you have any questions please feel free to ask to make things easier to understand.

Thank you so much :smiley:

For placement purposes, I’d suggest figuring out how to make active vertex (pivot mode) and the 3D cursor into your friends. That way you know you have a single point that should be consistent for snapping and snap-to-cursor(with offset). For moving objects you select a whole thing then shift deselect and re-select the single vertex you want as your precision reference point.

You can also place the 3D cursor somewhere on a mesh, then go to the N-panel to copy or paste certain values to or from the 3D cursor after that operation. It’s also handy with exact transforms or alignments. The usual workflow doesn’t make this too obvious though, as there’s no “align-to on X” type function. But manual inputs in this way with copy-paste serves as an equivalent.

As far as scaling in the way you mention? Might look into using mesh modifier. You make a fairly low poly cage around the higher detail mesh, and its vertices provide a manipulation reference for scaling or other operations that would warp or deform the mesh. In some cases that gives better control than proportional editing. It’s also more refined than the lattice modifier, which is a looser or more basic form of the same kind of functionality.

Then you can set an edge or two points as an axis for custom transforms. The hotkey for this is ctrl-alt-space, which is faster than going down the N-panel for the transforms menu. Constraining to an axis twice should go from global to the custom one, which is handy for movement/scaling/rotation operations.

Also don’t forget you can change the type of pivot center for scaling and rotation operations. It’s a thing that’s overlooked but powerful once you get how each one works. (As mentioned before, active vertex is one of the modes. Median point is the default mode.) So you can even do stuff like setting the 3D cursor as the pivot, snap it to one location, then rotate a selected object about that 3D cursor while having an active vertex reference for snapping in vertex mode - which will allow for rotating things into exact alignment.

Not sure how much that helps, but I’m sure you get the idea. :wink:

I have considered a very similar problem, also relating 3D scans. It seems Shrinkwrap might be useful http://www.raymairlot.co.uk/blog/the-shrinkwrap-modifier-a-hard-surface-modellers-best-friend

I have not put any time yet into working out whether it would really be useful but that link makes me think it could be.

You could try using lattice or mesh deform modifier to reshape the mesh resulting from flexed scan.