Geometry and coordinate frames

The fingertip exterior is 32.70 × 22.41 × 19.00 mm; its rear profile is 22.40 × 19.00 mm. OBJ positions, mounting translations, and simulator positions are stored in metres. Quaternions use (w, x, y, z).

Registration and mounting

The original layout aligns to the overmold interior by one translation of approximately (-2.775670, -0.0000166, -1.429237) mm in the sensor frame, with no scaling, additional rotation or individual taxel movement. Reference-CAD comparison gave 1.37 µm RMS and 4.29 µm maximum residual. Contact poses were then projected along the original normals through approximately 1.43 mm of overmold. assets/sensors/dex01/reference.json records this shift and the mounting offset. Offset quaternions use (w,x,y,z); translations and OBJ coordinates use metres.

Asset sources

The exterior OBJ and reference.json live under assets/sensors/dex01/. The mounted sensor and Tesollo hand USD assets live under assets/robots/tesollo/. Taxel NPZ files ship inside the Python package. Fetch them with git lfs pull.

The geometry builder and verification scripts are the reference workflow for changes; see attachment and validation.

Transform a contact sample

An NPZ pose stores its three local axes in columns 0–2 and position in column 3. Column 2 is the outward normal. First apply the mount rotation and translation from reference.json to obtain coordinates in the sensor rigid body. Then apply that body’s live world pose from PhysX. For a point p:

p_body  = R_mount p_pattern + t_mount
p_world = R_body  p_body    + t_body

Normals receive the rotations without translation. These are fixed mount transforms; the sensor’s live body pose changes as the hand articulates. The capture utility verifies world-space sample alignment against every mounted visual mesh.

Use the exterior pattern supplied by Dex01PatternCfg for contact sampling. The reference dex01_pattern.npz retains the original layout for traceability; it is not the projected exterior sampling surface. Both files keep the same taxel order and firmware pixel mapping.