How to fit a custom socket to a scan for prosthetics makers

Q: Is LunarWerx 3D Print free to use?

The tools are free to use. It runs in a web browser and you use it on its website, which is hosted on Cloudflare. Its tools are built for printer settings, moulding checks and foam packing.

A practical guide for prosthetics makers to fit a custom socket to a scan, with steps, tool options and common mistakes to avoid.

By TexHouse · 2026-10-23

TexHouse is published by the makers of LunarWerx 3D Print, Vector3D and MeshyDL, which are compared here alongside other tools.

Fitting a custom socket to a scan means turning a digital model of a residual limb into a socket shape, checking the fit, and adjusting the design until the socket is comfortable to wear. This guide covers what to have ready, the steps in order, tool options that can help with parts of the job, and mistakes to avoid. The steps stay the same whatever tools you use, so the page sticks to the process and says what each option does.

Option	What it does	Fee
LunarWerx 3D Print	Browser tools for ironing settings, moulding checks and foam packing for printed parts ^[1]	Free to use ^[1]
Other tools for scan fitting	Not covered by the facts on this page; check each tool's own documentation	Not published

What you need before you start

Before fitting a custom socket to a scan, have the scan itself ready and check that it is complete. The scan should cover the whole residual limb, including the end and the areas that will bear load or need pressure relief. Keep any notes from the prosthetist or clinician who will fit the final socket close to hand, since their guidance shapes the design.

You will need a way to view and edit the scan geometry. That could be a CAD program, a mesh tool or a dedicated socket package. You will also need a way to produce a trial socket, whether by printing it or by another method your clinic uses.

Keep a measuring tape, a marker and a notebook for recording each change. A socket is adjusted in small steps, and the changes are easy to lose track of without notes. Finally, plan for trials. The first socket is usually a check rather than the final fit, so set aside time to test it and return to the design.

Step by step

Check the scan. Confirm the scan is complete, and repair any holes, gaps or surface errors before you do anything else.

Mark the landmarks. Note the bony points, the areas that can take load, and the areas that need relief, so the design follows the limb rather than a generic shape.

Set the reference. Align the scan to a fixed reference such as the socket's axis, so later measurements can be repeated.

Offset the inner shape. Build an inner surface that follows the scan, with the allowances for soft tissue and any pressure relief the clinician has asked for. Keep the offset smooth, without sharp steps.

Add the socket wall. Give the wall a thickness that is stiff enough to hold its shape and comfortable at the edges. Check the rim against the limb.

Check the fit in the model. View the design from several angles and look for areas that press too hard or leave too much gap.

Make a trial. Produce a test socket in the chosen material and fit it to the limb with the liner or sock the clinician advises.

Record the feedback. Mark where the trial is tight, loose or sore, and write down the change that each mark calls for.

Adjust and repeat. Update the model for each recorded change, make a new trial, and check again until the clinician and the wearer accept the fit.

Tools that can do it

LunarWerx 3D Print is made by the team that publishes this site. Its tools are for printer and part work, which are different steps from fitting a socket to a scan. ^[1] It runs in a web browser ^[1], and you use it on its website, which is hosted on Cloudflare. ^[1]

For ironing, it works out settings for your printer, material and finish, and it exports a ready 3MF file. ^[1] It makes a 9-pad or 16-pad test plate around your settings, and you mark each pad as worked or not. ^[1] You can click flat top surfaces, and the export adds a modifier part over each picked surface. ^[1]

When you open an STL file with faces turned backwards, it turns them right side out and says how many it fixed. ^[1] Scan files can carry the same problem, so this check can be useful before you start a design.

Its moulding checks, shrinkage maps and mould halves are built for injection moulding parts, so they belong to the mould side of a project. ^[1] It also lays parts out in a box and designs a 3D-printable foam tray and top pad that each part lifts straight out of. ^[1] The foam insert is split into pieces that each fit your printer's bed. ^[1]

Sign in with Connections and your settings, recent test plates and print results follow you to every computer. ^[1] The code package is marked private, not public. ^[1]

Other tools may cover parts of this job. Check each one's own documentation for what it does, what it costs and whether it accepts your scan files.

Common mistakes to avoid

Fitting to an incomplete scan is a common mistake. Gaps in the mesh push the design into the wrong shape, so repair the scan first.

Skipping the trial is another. A model can look right on screen and still press on a bony point once it is worn. Test the socket on the limb before treating the design as final.

Making every change at once makes it hard to tell which change helped. Change one area at a time and record each change in your notebook.

Ignoring feedback from the person wearing the socket is a mistake too. Comfort is the test that matters most, so their marks on the trial should drive the next revision.

Treating the first design as final wastes time. Plan for more than one trial, and keep the notes from each one so the fit improves step by step.

Frequently asked questions

How do you fit a custom socket to a scan?

Start by checking that the scan is complete and repairing any gaps in the surface. Mark the bony points and the areas that need relief, then build an inner shape that follows the limb with the allowances the clinician asks for. Produce a trial socket, record where it is tight, loose or sore, and adjust the model for each mark. Repeat until the clinician and the wearer accept the fit.

Is LunarWerx 3D Print free to use?

The tools are free to use. ^[1] It runs in a web browser ^[1] and you use it on its website, which is hosted on Cloudflare. ^[1] Its tools are built for printer settings, moulding checks and foam packing. ^[1]

Can LunarWerx 3D Print check a part for injection moulding?

It checks a part for injection moulding and shows shrinkage, pressure and weak-point maps. ^[1] It also builds the two mould halves for a part. ^[1] All of its numbers are estimates. ^[1] Whether that process suits a socket is a question to settle with the clinician and the maker of the mould.

Can LunarWerx 3D Print fix backwards faces in a scan file?

When you open an STL file with faces turned backwards, it turns them right side out and says how many it fixed. ^[1] A scan exported as an STL can have this problem, so check the mesh before you start the design. It runs in your browser, and sign-in with Connections lets your settings, recent test plates and print results follow you to every computer. ^[1]

What should you check before choosing a tool for a socket scan?

Check whether the tool accepts your scan file format and whether it can work with the mesh as it is. Read the tool's own documentation for what it does, what it costs and where your files are processed. If it has a free part, try it on a scan you already know, and compare the result with the feedback from the wearer. Ask the clinician which steps they expect the tool to cover.

The tools are free to use. ^[1]

Try LunarWerx 3D Print

Sources

LunarWerx 3D Print's own description of itself (the product of this site's publisher)