Smaller downloads and faster transmission of 3D models and scenes will accelerate the widespread usage of 3D graphics in applications, browsers, and VR and AR platforms. The Khronos glTF Draco extension specification is accompanied by optimized, open source compression and decompression libraries on the Draco GitHub site to enable the rapid deployment of glTF compressed geometry into tools, engines, applications, and browsers everywhere. Draco is an open source library developed by Google for compressing and decompressing 3D geometric meshesintended to improve the storage and transmission of 3D models.
Draco was designed and built for high compression, efficiency, and speed. The code compresses vertex positions, connectivity information, texture coordinates, color information, normals, and any other generic attributes associated with geometry.
With Draco, 3D applications and assets can be significantly smaller without compromising visual fidelity. For users, this means that apps, scenes and models can now be downloaded faster, 3D graphics in the browser can load quicker, and VR and AR scenes can now be transmitted using a fraction of the bandwidth. The Draco extension to glTF enables creators to compress the mesh data within glTF files to dramatically reduce file size.
In sample glTF models, up to 12X compression has been demonstrated with no change in visual fidelity. Smaller glTF files will enable an explosion in 3D file availability across devices and applications, even on slow networks. The Draco team at Google is continuing to improve mesh compression ratios, decoder size and decode speed. The team is also investigating compression of animations and point clouds for inclusion into future glTF extensions.
Check out the open source Draco code on GitHub and use the issue tracker to tell us about successes and feature requests. Read more about glTF 2. For more information about The Khronos Group visit Khronos. The Khronos Group is an industry consortium creating open standards to enable the authoring and acceleration of parallel computing, graphics, vision and neural networks on a wide variety of platforms and devices.
Khronos members are enabled to contribute to the development of Khronos specifications, are empowered to vote at various stages before public deployment, and are able to accelerate the delivery of their cutting-edge accelerated platforms and applications through early access to specification drafts and conformance tests.
On October 19,the glTF 1. On September 6,Binomial announced plans to make their cross-platform texture compression format an open standard. On June 19,Oculus added glTF 2. Godot supports glTF 2. GLB file format is a binary form of glTF that includes textures instead of referencing them as external images.
Learn how and when to remove these template messages. This article relies too much on references to primary sources. Please improve this by adding secondary or tertiary sources. May Learn how and when to remove this template message. This article may need to be rewritten to comply with Wikipedia's quality standardsas there is too much focus on history.
You can help. The discussion page may contain suggestions. March This article contains content that is written like an advertisement. Please help improve it by removing promotional content and inappropriate external linksand by adding encyclopedic content written from a neutral point of view. March Learn how and when to remove this template message. Retrieved Virtual Globe and Terrain Rendering. Archived from the original on 19 March The Khronos Group.All Rights Reserved.
See Appendix for full Khronos Copyright Statement. This extension defines a schema to use Draco geometry compression non-normative libraries in glTF format. This allows glTF to support streaming compressed geometry data instead of the raw data. This extension specification is based on Draco bitstream version 2.
The conformance section specifies what an implementation must do when encountering this extension, and how the extension interacts with the attributes defined in the base specification. Figure 1 : Structure of geometry compression extension. The Draco extension points to the bufferView that contains the compressed data. Below is an example of what part of a glTF file will look like if the Draco extension is set.
Note that all other nodes stay the same except primitives :. The bufferView property points to the buffer containing compressed data. The data must be passed to a mesh decoder and decompressed to a mesh. Each attribute is associated with an attribute id which is its unique id in the compressed data. The attributes defined in the extension must be a subset of the attributes of the primitive. To request an attribute, loaders must be able to use the correspondent attribute id specified in the attributes to get the attribute from the compressed data.
The accessors properties corresponding to the attributes and indices of the primitives must match the decompressed data. Below is the recommended process when a loader encounters a glTF asset with the Draco extension set:. To prevent transmission of redundant data, exporters should generally write compressed Draco data into a separate buffer from the uncompressed fallback, and shared data into a third buffer. Loaders may then optimize to request only the necessary buffers.
Draco compression may change the order and number of vertices in a mesh. To satisfy the requirement that accessors properties be correct for both compressed and uncompressed data, generators should create uncompressed attributes and indices using data that has been decompressed from the Draco buffer, rather than the original source data. Some parts of this Specification are purely informative and do not define requirements necessary for compliance and so are outside the Scope of this Specification.
These parts of the Specification are marked as being non-normative, or identified as Implementation Notes. Where this Specification includes normative references to external documents, only the specifically identified sections and functionality of those external documents are in Scope.In Verge3D, scene files may be compressed using the highly effective LZMA2 compression algorithm, thus allowing to significantly reduce the size of the files.
Draco Compressed Meshes with glTF and 3D Tiles
At the same time, LZMA2 offers fast decompression on the browser side. Typical compression rates observed for Verge3D scenes are: 20x for the. Verge3D supports loading of scene files compressed in the. To enable creating. The compressed. What is left is to enable loading them in your app. To do this, go to Puzzles Drag out the configure application puzzle from the Initialization category, if it is not already present in the workspace, and turn on the compressed assets checkbox on it:.
To ensure that your app now actually loads compressed assets, run your app either from App Manager or from a website where it is deployed.
Open the browser console and switch to the Network tab. Reload your app so that the console starts displaying files from the beginning. Find the scene files in the list - if everything is ok, they should end with. If you don't want to use Puzzles for some reason, follow these steps to enable asset compression for your apps.
For Player-based applications that have a scene. The same applies to. Alternatively, you can create.How to Compress High Quality Animations
Verge3D implementation of an. Considering this, it's recommended to use settings described below. Also you can use a command line version of 7-Zip instead: 7z. Its Windows binaries are available here in the Pre-built binaries section.
The usage is simple: xz. The usage is similar to the one in Windows: xz -k -f -6 scene. The usage is the same as in Linux.Everyone is welcome to contribute to the code and provide feedback about the specification; you do not have to be a Khronos member to participate in the glTF community. The original Blender file will be provided to the glTF community for free! Please provide spec feedback by submitting issues. For technical or art workflow questions, or to showcase your work, join the glTF forum.
For quick questions, use the gltf channel in the Khronos Group Slack.
Compression in GLTF?
From github. We believe the true usefulness of glTF goes beyond the spec itself; it is an ecosystem of tools, documentation, and extensions contributed by the community. You are encouraged to get involved! Toggle navigation.
Runtime 3D Asset Delivery. Metallic-Roughness Material model baseColor — base color metallic — metalness roughness — roughness Simple to implement - mandated in core. Specification glTF Specification, 2. Quickstart Overview From github. Drag-and-drop validator for verifying correctness of existing glTF files. RapidCompact Multiple Optimizes and converts 3D assets for efficient online presentation. Also create degree VR content and embed 3D glb assets in the scene.
Datakit CrossManager converter Multiple File converter. Supports multiple 3D formats inputs and outputs, including glTF output. Graphical interface or command-line Optimizers Tool Status Description gltf-import-export NPM package to convert between glb and gltf files makeglb Drag and drop browser tool to convert gltf to self contained binary glb gltf-toolkit Collection of tools and libraries to modify and optimize glTF assets for Windows Mixed Reality home glTF Pipeline Official Node.
Gestaltor Native application for viewing, inspecting, editing, composing and optimizing glTF. Engine Status Scope Related three. JS loader All Grimoire. Examples xml3d. Poly Google service glTF models hosted on Poly may be embedded in an iframe on any site. Sketchfab Sketchfab service glTF models hosted on Sketchfab may be embedded in an iframe on any site, using the embed models feature. November Using the Babylon. October If you build it togetherthey will come July Why glTF 2.
June Sketchfab uses glTF to bring a search bar to the world of 3D. September State of glTF 2. September glTF Exporter in three. August glTF 2.
August Why we should all support glTF 2. August Exporting glTF 2. June glTF 2. March Call for feedback on glTF 2. December Bringing 3D to everyone through open standards by Forest W. Gouin and Jean Paoli. July glTF Update and Roadmap.I do work very hard to reduce the complexity of the meshes and objects before they are exported, but there is a limit to what can be achieved with this strategy. This ratio varies depending on the content of the BIN file.
Its compression ratios are not very good. I have done some experiments with other algorithms. Web server load. This would be wasteful.
I am aware that a team at Google is working on a mesh compressor called Draco. It achieves amazing compression ratios. Other teams are working on incorporating Draco in three. Does anyone have thoughts on compression strategies for our projects? Should we wait for the GLTF Draco extension or should we investigate a pre-compression strategy while the Draco work completes? Thank you, -Jem. On the other hand, the Draco mesh compressor seems to be an interesting approach too although at the expense of precision and certain processing power.
I think we can look closer at this technology once it is natively supported by the glTF format. Hi Yuri, Thank you for the response. Your response inspired me to test several different bin files against several different compressors. I found the results interesting. The bin files in your E-Learning example are very compressible. The bin files that I have created are not.
I was able to reproduce your 7-fold reduction when I used the E-Learning files. I could only reduce my bin files by half. My files might be a special case. My meshes originated in a CAD system. Although I simplified the models as much as possible, they still carry traces of their origin.
On Draco… I understand that it is lossy. As I understand Draco, it uses configurable vertex quantization. Maybe my meshes could benefit from losing a few least significant bits? The example contains client data, so I must share it with you privately. I will send you the file. If it helps the discussion, I can create some non-confidential CAD models so we can discuss them openly in the forums.
Thank you, Jem. This topic has 5 replies, 2 voices, and was last updated 2 years, 2 months ago by Yuri Kovelenov. Viewing 6 posts - 1 through 6 of 6 total.Draco is a glTF extension for mesh compression along with an open-source library developed by Google to compress and decompress 3D meshes to significantly reduce the size of 3D content.
It compresses vertex positions, normals, colors, texture coordinates, and any other generic vertex attributes, improving the efficiency and speed of transmitting 3D content over the web. This means smaller file sizes and faster streamingparticularly in the case of 3D Tiles, which frequently streams new glTF models when new tiles come into view or a new level of detail is required. We have been collaborating with Khronos and Google to make Draco a glTF extension, and you can now load Draco compressed models and 3D tilesets in Cesium!
Starting with Cesium 1. Using compressed meshes reduces the resulting file size of a glTF model, meaning these assets take up less space, download less data, and stream faster.
To illustrate the difference, we compressed the following files using the Draco encoderwith the default compression level of 7 for all attributes.
Since the extension only compresses geometry, the texture payload CesiumMilkTruck. The additional JSON metadata created with the extension has little impact on the. We see a smaller. When using 3D TilesCesium frequently makes requests and streams new 3D content. In terms of loading times, while we take a small initial hit when performing the overhead of loading and compiling the Draco module Web Assembly, afterwards all tiles stream and decompress more quickly than they would without Draco compression.
Cesium takes advantage of Web Workers to decode multiple meshes in parallel. In the case of 3D Tiles, this means multiples tiles can be streamed and decoded simultaneously. Furthermore, each primitive or part of a mesh can be decoded separately for faster decoding of complex models. We can retrieve each segment of the encoded buffer and pass the data to separate workers to asynchronously decode in parallel before returning the data necessary to render the mesh to the main thread.
Vertex attributes that are usually stored as bit floating point numbers, such as position attribute data, can be decoded as quantized bit integer values. Additionally for attributes that are unit vectors such as normals, we can decode as oct-encoded data. When decoding on the GPU, we skip the quantization or octahedron transform operation in the Draco decoder module and instead retrieve and store any transformation constants.
The smaller decoded data can be passed to the GPU where the dequantization or oct-decoding operations are performed in the shader when rendering. This results in a smaller memory footprint, both in the main application thread running on the CPU and in parallel on the GPU. Look for loading your own Draco compressed models in Cesium 1. Use this glTF-pipeline branch with in-progress Draco compression to apply Draco mesh compression to an existing glTF asset.
Let us know how Draco compression impacts your models by tweeting the results to us, CesiumJS. Get started with Cesium ion. Gabby contributes to open source CesiumJS and 3D Tiles, and works closely with users as well as the 3D, geospatial, and open source communities.
Connect with Gabby :. Sign up for free. Draco Compressed Uncompressed File 2.