The visual meshes

    roqsim_sensors/models/zivid/meshes/zivid_body.obj  (dark camera housing)
    roqsim_sensors/models/zivid/meshes/zivid_fov.obj   (square FOV coverage frustum)

are derived from Zivid's official Zivid 3 CAD model: the binary STL `Zivid 3.stl`
(SolidWorks 2024 export, header 'stlbn Zivid 3', mm units, Z up) published by Zivid
among the Zivid 3 product resources at https://www.zivid.com (CAD downloads, files/CAD/).
A matching STEP file (`Zivid 3.step`, SwSTEP 2.0 / SolidWorks 2024, AP203) is published
alongside it; the STL is used here because the housing is a single dark part with no CAD
materials to split, so no STEP->tessellation step is needed.

The body geometry is identical across the Zivid 3 product family; the XL250 variant's
optical parameters (39 deg square FOV, 2.5 m focus distance, 250 mm baseline) come from the
Zivid 3 XL250 datasheet, not the mesh. The FOV mesh is not from CAD -- Zivid ships no FOV
solid -- it is a datasheet-authored square pyramid out to the 2.5 m focus distance
(1750 x 1750 mm field of view at focus).

Conversion pipeline (no housing geometry authored by hand):

    STL -> OBJ    Blender: scaled mm -> m, centred on x=y=0 with the base dropped to z=0,
                  decimated (~8k tris), exported axes 1:1 with Z up.
    FOV  OBJ      Blender: authored square frustum (39 deg, apex at the optical origin,
                  far plane at the 2.5 m focus distance).

The underlying CAD geometry is Zivid AS's and its copyright remains with Zivid; it is
redistributed here only as a decimated simulation asset for the Zivid 3 XL250 sensor
model. Refer to Zivid's terms for the original CAD. If Zivid's terms do not permit
redistribution of this derived mesh, remove these two .obj files and the mesh geoms in
zivid.xml -- the `zivid` capture plugin does not need them (it renders from the
`zivid_color` camera), and a primitive-only housing can stand in.