| name | bench-camera-scene-alignment |
| description | Before debugging a gray/black bench frame, verify the camera Y-position matches scene geometry Y-level — a camera 20 units above ground looking horizontal sees nothing below the viewport, producing gray frames indistinguishable from rendering pipeline failures. |
| source | auto-skill |
| extracted_at | 2026-06-16T02:10:00.000Z |
Bench Camera-Scene Alignment Pitfall
When a custom bench produces solid gray or black frames with no visible
geometry, check this FIRST before diving into render-pipeline debugging.
The trap
A camera positioned at (0, 25, 0) looking horizontally at
(0, 25, -10) with FOV 60° has a vertical field of view of roughly
±5.7 units at 10m distance. If all scene geometry is placed at y=5
(the default for many bench scenes), the geometry is 20 units below
the camera's sight-line — completely outside the viewport. The result
is a solid gray/black frame indistinguishable from a rendering
pipeline failure.
The check
- Compare
camera_y position to geometry_y position.
- Verify the vertical offset is within
distance * tan(fov_y/2).
- Ensure the
look_at point is at the same height as the geometry,
not the camera.
Titan specifics
- The
titan-render-bench default camera is at (0, 25, 35) looking
at origin — it sees a ground plane at y=0 because the camera is
above and angled downward (~45°).
- A center-facing camera at
(0, 5, 0) looking at (0, 5, -10) sees
geometry at y=5 because the look direction is horizontal at the
same height.
- If the camera uses a different height than the cubes, the look-at
must be adjusted to point at the cube height.
