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How-to: Hand Braces

Task-oriented guides for hand and wrist brace design.

How do I set the thumb diameter?​

The thumb tube of a hand splint is shaped from the Thumb section, which appears in the Correct step of a hand splint only.

  1. Open the Brace (Hand splint) document and go to the Correct step.
  2. In the right-hand settings panel, find the Thumb section. It is always there for a hand splint. You do not add it.
  3. Set Diameter in mm (range 0 to 50). The model recalculates immediately.
  4. Every change is recorded in the History. Uncheck the correction there to revert it.

See also: Correct

How do I draw the four hand trim sections?​

A printed hand splint is trimmed with four separate hand-specific trim lines in the Design step. A milled brace has no Design step.

  1. Open the Design step. If you want anatomical references first, add Markers and click once per landmark as the view rotates to each (metacarpal heads, radial styloid, and so on).

Thumb, palm and arm cuts:

  1. Add the trim section you want: Trim line - Thumb, Palm, or Arm.
  2. LutraCAD auto-computes the limb centre line. Click once on that line to choose the cut height. A red cross-section previews the cut.
  3. Repeat for each of the three sections.

Dorsal connector:

  1. Add Dorsal connector.
  2. Click once on the palm line. A connector to the arm centre line previews, joining the palm and arm parts across the back of the hand.

See also: Design

How do I set the dorsal opening?​

The dorsal opening sets the gap of the top connector on a printed hand splint. It lives in the Design step.

  1. Open the Design step.
  2. Set Dorsal opening in mm (range 2 to 30 mm). This is the width of the opening across the dorsal connector.
  3. To soften where the parts meet, set Fillet distance in mm (range 3 to 20 mm). This fillets the connection points.
  4. Values apply on Enter or when you click away, and the model recalculates immediately.

See also: Design

How do I add strap cutouts?​

Strap cutouts on a hand splint are added per strap group in the Design step.

  1. Open the Design step.
  2. Set the Straps type for the thumb and pinky groups. Choose one of: None, Rivet anchor hole, Rivet return slot, or Strap loop.
  3. Set Distance to edge (range 5 to 20 mm) to keep the cutouts clear of the trim edge.
  4. Set Amount (range 0 to 20) for how many cutouts to place. The model recalculates immediately.

See also: Design

How do I add a hole pattern?​

A hex hole pattern perforates the shell for ventilation and weight. It is available on all brace variants in the Design step.

  1. Open the Design step.
  2. Add Hole pattern.
  3. Set the Hex size and Hex distance in mm (range 0.5 to 10 mm) in the settings panel.
  4. Use Edit to draw the region the pattern fills: click a series of points on the model (a red curve preview follows), then right-click or press Enter to close the loop, and confirm.
  5. Use Mirror to copy the pattern to the other side.
  6. For individual holes instead of a hex field, add Cut out and draw its curve the same way.

See also: Design

How do I adjust a smooth or volume region?​

Smooth and volume regions are local edits available on all brace variants in the Correct step.

Volume region (local push or pull):

  1. In the Correct step, add Volume region.
  2. Click a series of points on the model to mark the region, then finish the curve.
  3. Set the Amplitude (0.5 to 100) to push out or pull in, and the Radius in mm (0.5 to 100 mm) for how far the deform blends.

Smooth region (local smoothing):

  1. Add Smooth region and draw its region the same way.
  2. Set the Factor (1 to 10) and the smooth Distance in mm (1 to 100 mm).

Overall smoothing:

  1. To smooth the whole brace instead of a region, set Smooth (0 to 10).

See also: Correct

How do I export a hand splint?​

A hand splint is printed, so it exports through the Export step after the Design and Printing steps.

  1. Before exporting, open the Printing step and set the wall Thickness (range 1 to 10 mm) and Flare (0 to 10 mm).
  2. Open the Export step.
  3. Choose your route:
    • Export writes the brace as an STL.
    • Save order packages an .l3z order for outsourcing.
    • Produce now or Place in production sends it to in-house 3D print production.
    • When an order system is configured, pick a partner in Outsource to and use Place order.
  4. A printed brace routes to 3D print production. The milling dialog is only used for a milled brace.

See also: Printing, Export