Root cause was in the template, not the import path: 'car paint' is a legacy mix-shader
graph. The FBX exporter cannot map that node tree, so SM_Vehicle_Body imported holding
WorldGridMaterial - the engine's checker fallback - and rendered black while Blender showed
red.
Two changes:
- Tools/vehicle_from_template.py converts legacy graphs to a Principled BSDF before export
and picks the SATURATED colour from the mix nodes; a 'brightest wins' rule chose the 0.8
grey diffuse beside the 0.49 red and produced a grey car.
- Tools/ue_vehicle_materials.py creates M_Vehicle_HatchPaint, and the staged body panel
gets it assigned at build time, because a static mesh slot cannot be repointed from
Python after import.
Judge on the new capture: verdict=yes confidence=0.9 - 'a red hatch car with a red body and
dark wheels parked on a road'. The comparison table in Screenshots/README.md now shows both
columns agreeing on colour.
Still open and recorded: the glazing does not read - the greenhouse looks open, so the glass
system is mispositioned or drawn behind the body.
Merged COMPARISON.md into the review README as a generated section between
<!-- blender-comparison:begin/end --> markers, so there is one place to look and one place
to sign off. Tools/build_comparison_md.py rewrites only that block - the hand-written
sections around it are untouched - and formats the file with prettier afterwards, because a
generated table is never byte-identical to prettier's output and the repo gates on
--check.
Run it after every capture or Blender render; it is the routine that keeps the page current
with new images rather than a one-off export.
The invisible-vehicle defect is closed. Shot 9 now shows the car instead of an empty road.
Tools/vehicle_from_template.py converts Art/blender/vehicle/hot hatch.blend into UE-ready
assets, following two skills:
vehicle-artist - systems split (body 113k tris, trim 10.5k, glass 20.5k, lights 18.6k,
wheels 47.8k), one UCX_ hull 1.45 x 3.94 x 0.76 m, two decimated LODs at 39.7k and 13.6k.
unreal-export - scale normalised to a documented 4.05 m hot hatch before export (the
template measures 7.26 m, factor 0.5579), then verified after import: body bounds
1.51 x 4.02 x 1.22 m against the 4.05 m target.
Staged as five plain StaticMeshActors, because the earlier probe proved those render while
the same meshes attached to the vehicle pawn do not.
Open and recorded rather than hidden: judge_screenshot returns verdict=no confidence=0.9 -
the silhouette does not read as a hot hatch from this angle and the car floats slightly.
The likely causes are a system misclassification in the template conversion and an
origin-height error of a few centimetres.
zwitschi