PLY — Signpost, +Z up (comment only)
The signpost as ASCII PLY with +Z up. PLY has no axis or unit element, so the convention survives only as a header comment that no parser reads — the reason scan data so often arrives rotated.
Interactive preview rendered from the equivalent glTF (signpost-z-up.glb); drag to orbit. Download the file above for the PLY original.
Specifications
- Format
- PLY (ASCII)
- Up Axis
- +Z
- Declares Axis
- false
- Axis Record
- header comment
- Vertices
- 144
- Faces
- 48
Testing contract
Reference control- Scenario
- Parse the file and try to determine its up axis programmatically.
- Expected result
- Nothing machine-readable states it; the only clue is a comment, so orientation has to come from out-of-band knowledge or from measuring the geometry.
What is a .ply file?
PLY (.ply, Polygon/Stanford Triangle Format) is a flexible 3D format storing a list of vertices and faces with arbitrary per-element properties (position, colour, normals, confidence), in ASCII or binary. It is standard for scanned meshes and point clouds.
How to use this file
Use an example .ply file to test mesh/point-cloud parsers (Open3D, MeshLab), per-vertex colour handling, and PLY conversion.
How to use this file for testing
“PLY — Signpost, +Z up (comment only)” is a deterministic Novus Examples fixture for Conversion testing, Metadata testing, Mesh processing QA. The same content exported across many formats and linked as a group, so you can convert one and diff against the expected twin.
Documented properties for this file: PLY (ASCII). Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
3D and CAD fixtures carry one small, documented solid or scene. Convert and inspect against the known geometry, units, and structure; format twins let you diff interchange fidelity, and the 3D viewer previews the actual mesh.
Code examples
import trimesh # pip install trimesh
mesh = trimesh.load("signpost-z-up.ply")
print(mesh.bounds, mesh.faces.shape)Related files
- daeDAE — Signpost, Y_UP declaredThe same signpost as COLLADA with `<up_axis>Y_UP</up_axis>` and `<unit meter="1" name="metre"/>` in its asset block. Unlike glTF, OBJ and STL, COLLADA states its convention — so an importer that still gets the orientation wrong has no excuse.
- glbGLB — Signpost authored in CentimetresA 1.12 m signpost with its coordinates written in centimetres — so this file's numbers read up to 112. glTF has no unit field: the spec simply says metres, which means a wrongly-scaled export is indistinguishable from a genuinely enormous model until something is measured.
- glbGLB — Signpost authored in MetresA 1.12 m signpost with its coordinates written in metres — so this file's numbers read up to 1.12. glTF has no unit field: the spec simply says metres, which means a wrongly-scaled export is indistinguishable from a genuinely enormous model until something is measured.
- glbGLB — Signpost authored in MillimetresA 1.12 m signpost with its coordinates written in millimetres — so this file's numbers read up to 1120. glTF has no unit field: the spec simply says metres, which means a wrongly-scaled export is indistinguishable from a genuinely enormous model until something is measured.
- glbGLB — Signpost, Y-upThe signpost authored +Y up, which is what the glTF specification mandates and what every conformant viewer assumes. The conformant half of the axis pair: load it, confirm the post stands, and you have calibrated your viewer before testing the Z-up twin.
- objOBJ — Signpost authored in MetresThe same signpost as OBJ with coordinates in metres. OBJ has no unit record of any kind, so the two OBJ files in this group are byte-different and semantically identical — the ambiguity that every OBJ import dialog's scale box exists to resolve.
Generated by generation/models_p7.py. Free for any use, no attribution required — license.