# Is there any documentation for tiling 3DGS (.ply) files? **URL:** \ **Category:** Cesium ion\ **Created:** [March 25, 2026, 12:31pm UTC](https://community.cesium.com/t/is-there-any-documentation-for-tiling-3dgs-ply-files/45654 "2026-03-25T12:31:11Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![will\_riddy](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/will_riddy/32/28173_2.png) [@will\_riddy](https://community.cesium.com/u/will_riddy)\ **Post date:** [March 25, 2026, 12:31pm UTC](https://community.cesium.com/t/is-there-any-documentation-for-tiling-3dgs-ply-files/45654/1 "2026-03-25T12:31:11Z")
Hi, I haven’t had much success with tiling 3DGS .ply files. Is there any documentation about the structure a .ply file needs to follow to be successfully tiled? Thanks in advance. ---
**Author:** ![Marco13](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/marco13/32/2757_2.png) [@Marco13](https://community.cesium.com/u/Marco13)\ **Post date:** [March 25, 2026, 1:21pm UTC](https://community.cesium.com/t/is-there-any-documentation-for-tiling-3dgs-ply-files/45654/2 "2026-03-25T13:21:32Z")
I think that there is no “official” documentation for that - at least, not on this low technical level. One problem is that the concept of “splat PLY files” is underspecified. The PLY format _itself_ is specified clearly. But a PLY file can literally contain _anything_. However, there is a “de-facto” standard of what constitutes a “splat PLY file”. This happened “by chance”, derived from some research paper that made splats popular. Most of the common splat-generation tools do export splats in PLY files with this format. And this format should have a header like this one: ```auto ply format binary_little_endian 1.0 element vertex 9 property float x property float y property float z property float opacity property float scale_0 property float scale_1 property float scale_2 property float rot_0 property float rot_1 property float rot_2 property float rot_3 property float f_dc_0 property float f_dc_1 property float f_dc_2 property float f_rest_0 property float f_rest_1 property float f_rest_2 property float f_rest_3 property float f_rest_4 property float f_rest_5 property float f_rest_6 property float f_rest_7 property float f_rest_8 property float f_rest_9 property float f_rest_10 property float f_rest_11 property float f_rest_12 property float f_rest_13 property float f_rest_14 property float f_rest_15 property float f_rest_16 property float f_rest_17 property float f_rest_18 property float f_rest_19 property float f_rest_20 property float f_rest_21 property float f_rest_22 property float f_rest_23 property float f_rest_24 property float f_rest_25 property float f_rest_26 property float f_rest_27 property float f_rest_28 property float f_rest_29 property float f_rest_30 property float f_rest_31 property float f_rest_32 property float f_rest_33 property float f_rest_34 property float f_rest_35 property float f_rest_36 property float f_rest_37 property float f_rest_38 property float f_rest_39 property float f_rest_40 property float f_rest_41 property float f_rest_42 property float f_rest_43 property float f_rest_44 end_header ``` (The order of the properties does not matter. The `f_rest_` properties are optional) If you encounter any issues when tiling such a PLY file, then it could be good to describe the error more specifically, if possible. I know, it won’t tell you more than “Something went wrong”, unfortunately. So maybe when you post the ‘asset ID’ of the asset where the tiling processed failed, someone can have a closer look. ---
**Author:** ![will\_riddy](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/will_riddy/32/28173_2.png) [@will\_riddy](https://community.cesium.com/u/will_riddy)\ **Post date:** [March 25, 2026, 2:23pm UTC](https://community.cesium.com/t/is-there-any-documentation-for-tiling-3dgs-ply-files/45654/3 "2026-03-25T14:23:51Z")
Thanks @Marco13 🙂 that’s really useful. Do you also know if there will be native support for .spz files within Ion? ---
**Author:** ![Marco13](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/marco13/32/2757_2.png) [@Marco13](https://community.cesium.com/u/Marco13)\ **Post date:** [March 25, 2026, 3:23pm UTC](https://community.cesium.com/t/is-there-any-documentation-for-tiling-3dgs-ply-files/45654/4 "2026-03-25T15:23:51Z")
Support for SPZ files as the _input_ for the tiling _could_ be fairly easy. But there actually are good reasons to **not** offer this: SPZ is a _(lossy) compressed_ format. And it has some limitations for its use as a “general format for splats”. For example, it will quantize the _positions_ of the splats, to 12 bits by default. This means that it cannot represent “large value ranges”. I stumbled over this, with some details summarized in [Question about position encoding · Issue #52 · nianticlabs/spz · GitHub](https://github.com/nianticlabs/spz/issues/52#issuecomment-3217258916) . On top of that, the other compression approaches in SPZ (like quantization for spherical harmonics) will cause small errors. And when the _input_ data already has small errors, and is passed through the tiling pipeline, and then _written_ as SPZ, this will “accumulate” additional errors, meaning that this may cause some rendering artifacts or low(er) visual quality in the final output. In general, the _input_ for any processing pipeline should preferably be an _uncompressed_ (or _losslessly_ compressed) format. (We might think about the option to upload ZIPped PLY files, for example, just to save on transmission size…) An aside: Cesium ion is currently _writing_ glTF assets with SPZ-compressed splat data by default. And this makes sense: It is in a form that is intended for “last-mile” delivery, and should therefore be in a compact representation. Limitations of SPZ - like the limited value range for the positions - are not so critical when the data is divided into smaller tiles. However, sooner or later someone _will_ upload a “large” model (i.e. with a large spatial extent), and the position limitations will kick in. I already opened an issue for that. People can call this “pessimism” or “foresight”, but right now, I’m just waiting for that issue to become “active”, so to speak.