Fit to your hand
The measuring page fits the grips to your hand: it measures a photo of it and downloads print-ready STLs of Photon, Spark or both, for one hand or both, in one zip. Its steps are on the page. This chapter explains the values it computes and how to export the same parts yourself. To print the STLs of the zip as they are, skip it and go to Printing.
Values
Photon places each roller from three values per finger, relative to the pinky:
| Value | Meaning | Computed from |
|---|---|---|
Height | Roller up/down | Fingertip position in the OpenGrips claw grip (proximal phalanx vertical, PIP and DIP flexed 55°), including how far each base crease sits along the hand |
Depth | Roller forward/backward | Same claw grip, front-to-back fingertip position |
To_Blocker | Roof height: roller top to blocker | DIP→tip / tan(angle), with angles of 57° (index), 60° (middle, ring) and 55° (pinky) |
The original OpenGrips instructions set Height to the full finger length minus the pinky’s. That
rule ignores that the pinky starts lower on the hand, which put the rollers 8–14 mm too low on the
measured example hand.
Photon’s frame length follows the middle finger, so no other finger’s Height + To_Blocker may
reach much past the middle finger’s. Once every point is placed, the page checks the values against
the model itself and shows its message when a grip cannot be made from them.
The values do not depend on which hand the photo shows, so one photo can fit both hands; the model is a left-hand grip and the right hand is its mirror.
Exporting yourself
Each folder of the zip holds parameters.txt, the values the parts were rendered with, and the
clicked points. With OpenSCAD 2025 or newer installed, scripts/export.py
exports the same STLs from it, e.g. after editing a value:
python3 scripts/export.py photon crimpdeq-grips-photon-right/parameters.txt --hand right --out my-right-hand
For a Bambu Lab A1, scripts/export_bambu_project.py turns a folder of STLs into a Bambu Studio
project with all parts on one plate and the settings of Printing:
python3 scripts/export_bambu_project.py crimpdeq-grips-photon-right --output my-right-hand.3mf
It needs Bambu Studio installed and slices the project to check it.