The Complete VRM to USD Conversion Guide
General Information
This guide is part of the RapidPipeline 3D Formats Knowledge Database. It shows how to convert VRM to USD, if you'd like to know more about the formats, please check out the following links:
Comparison of Features Supported by VRM and USD
| Feature | Supported by VRM | Supported by USD |
|---|---|---|
| Morph Targets | Yes | Yes |
| Rigid Animations | Yes | Yes |
| Skinned Animations | Yes | Yes |
| Animations | Yes | Yes |
| Free-Form Surfaces | No | Yes |
| Geometry Compression | Yes | No |
| Quad Meshes | No | Yes |
| Basic 3D Geometry | Yes | Yes |
| PBR Materials | Yes | Yes |
| Transparent Materials | Yes | Yes |
| Vertex Colors | Yes | Yes |
| Materials | Yes | Yes |
| Scene Composition | No | Yes |
| Hierarchical Scene Graph | Yes | Yes |
| Scene Nodes | Yes | Yes |
| Standardized Format | Yes0 | Yes |
| Embedded Textures | Yes | No |
| Multiple UV Channels | Yes | Yes |
| Normal Mapping | Yes | Yes |
| Procedural Textures | No | Yes |
| Texture Compression | Yes | No |
| Texture Transforms | Yes | Yes |
| Texturing | Yes | Yes |
Limitations of a VRM Files to USD Conversion Workflow
The following limitations should be taken into account when converting VRM files to USD format:
| VRM Feature (not supported by USD) | Limitation Details |
|---|---|
| Geometry Compression |   Geometry Compression: supported in VRM, but not in USD. Geometry compression describes the process of compressing the representations of a 3D model's geometry, usually a triangle mesh. 3D geometry compression does not change the topology of a 3D model, but just changes the way that a 3D model and its 3D positions and related vertex data is stored. Geometry compression can be lossy (just like JPEG compression in image processing can be lossy, for example), in which case one might notice slight artifacts like variations in 3D vertex positions (compared to the uncompressed 3D model). However, such differences are often not noticeable. There are only very few standards for geometry compression, like glTF's support of Draco compression and similar extensions. |
| Texture Compression |   Texture Compression: supported in VRM, but not in USD. Texture compression refers to a process of compressing 2D texture images for memory-efficient rendering (and sometimes for efficient transmission). The decompression of compressed texture data is therefore performed on-the-fly during rendering, so that it never has to be stored in unpacked form, but can be kept as-is in GPU memory. Formats supporting texture compression methods, such as the ones offered by glTF through KTX2 containers, therefore allow 3D models to use a smaller memory footprint on the client device during rendering. This can speed up rendering time, and also make it possible to store and use larger amounts of texture data than it would otherwise be possible. |
| Embedded Textures |   Embedded Textures: supported in VRM, but not in USD. Embedded textures allow the storage and exchange of an entire 3D model and its materials within a single file, by embedding the texture images directly into the 3D file (and not storing them as separate image files). Without support for this feature, textures have to be stored in separate image files, and referenced from the main 3D model file. |
Converting and Optimizing VRM Files to USD
There are various ways to convert between VRM and USD. With RapidPipeline, you can easily convert and and optimize VRM files, at scale. It supports USD, as well as many other file formats (examples: 3dsMax, FBX, glTF, OBJ, PLY, STEP, STL, USDZ), at high quality.
Due to the potential limitations aforementioned on the table above, in principle, one cannot always perfectly convert 3D data between USD and other formats. In the following, you can find conversion guides between USD and the most important other formats, along with a rough score for compatibility of this workflow:
What's the best way to get VRM files into my 3D applications, and are there alternatives to using USD?
Doing 3D conversion right, especially at scale, can be tricky, as 3D data is in general a rather complex (yet very powerful!) medium. This also applies to VRM and USD files - the conversion guide above provides a rough first idea about that. Once you know what you would like to do, tools like RapidPipeline can help you perform the necessary steps, and to even automate the process for thousands or even millions of files.
Especially when introducing pipelines and workflows at scale in an enterprise context, it is usually good to rely on dedicated tools and expertise, making sure you do not introduce any steps into your 3D workflow that are detrimental to the final output's quality, or that take your team too much time (and money).
If you're interested to hire dedicated expertise from the best in the field to help your company reach your goals fast and reliably, please do not hestitate to contact DGG. Being the creators of RapidPipeline, and ambassadors for open 3D standards for more than a decade, we have been building some of the world's most advanced 3D pipelines, having processed many millions of 3D assets.
Therefore, our expertise will help you to reach your goals faster, at scale, and with the least possible friction, since we are focused on maximum interoperability.
To get started with 3D data conversion and optimization today, sign up for a free account!
If you have any questions, feel free to chat with our human team.
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