The Complete 3MF to AutoCAD Conversion Guide

Geometry Compression Support:

3MF: Partial support | AutoCAD: No support

3MF Notes:

ZIP-based compression of model data

Impact:

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.

Texturing Support:

3MF: Full support | AutoCAD: Partial support

AutoCAD Notes:

Basic texture mapping capabilities primarily through material assignments and visual styles, not as comprehensive as dedicated 3D graphics applications.

Impact:

Texturing describes the process or refining the visual appearance of a 3D model's surface through additional 2D or 3D data, defined in a different reference system. The by far most common use of texturing are 2D texture images, applied to model visual material properties the 3D surface. Other cases include the use of procedural 2D or 3D funtions that produce intensity or color signals, which are then mapped to the 3D surface. For the vast majority of these cases (all of them except for 3D procedural functions), a parameterization or "Texture Mapping" is needed, which maps the 2D content to the 3D surface. Coming from a 2D coordinate space with coordinate axes often entitled U and V (in contrast to XYZ, which are the 3D surface positions), this process of mapping is also called UV Mapping, and it can be done with a dedicated UV map, or through a live mapping (e.g., box mapping). In this example, a texture image is applied to the 3D model to give the control panel a realistic look. Without support for texturing, the panel would have to use a single material instead, or all controls (including text) would need to be modeled through 3D geometry, instead of a 2D texture image.

Texture Compression Support:

3MF: Partial support | AutoCAD: No support

3MF Notes:

Compressed textures within ZIP package

Impact:

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 Support:

3MF: Full support | AutoCAD: Partial support

AutoCAD Notes:

Textures can be referenced and included with drawings but with limited embedding capabilities compared to dedicated 3D formats.

Impact:

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.

Materials Support:

3MF: Full support | AutoCAD: Partial support

AutoCAD Notes:

Basic material properties for visualization and plotting purposes, primarily focused on appearance rather than physical material characteristics.

Impact:

Materials are a fundamental concept in 3D modeling, enabling colored and - in many cases - photorealistic rendering of the 3D model that they are applied to. There are also some formats that don't make use of 3D materials, for example because they need to solely describe a shape (e.g., for many cases in additive manufacturing). In this example, photorealistic PBR materials are used to equip the 3D model with a realistic look. Without support for materials, the model will have to be rendered with a default material (often a default shade of gray).

PBR Materials Support:

3MF: Partial support | AutoCAD: No support

3MF Notes:

Basic PBR material properties

Impact:

PBR materials enable Physically-Based-Rendering (PBR) for a standardized, photorealistic look of rendered images. PBR uses concepts like metallic-roughness or specular-glossiness properties and a microfacet-based modeling of the surface, using a concept called BRDF (Bi-Directional Reflectance Distribution Function). In this example, PBR materials are used to achieve realistic looking plastic and metal materials. Without support for PBR materials, only basic colors and shading can be used (for example, based on more simple shading models, such as the Blinn/Phong model).

Vertex Colors Support:

3MF: Full support | AutoCAD: Partial support

AutoCAD Notes:

Limited per-vertex color support, mainly through object properties and layer-based coloring rather than true vertex color manipulation.

Impact:

Vertex colors allow the attachment of colors to each vertex of a 3D model. This can be useful in scenarios such as scientific visualization, or when converting/meshing data from a colored 3D point cloud, for example. On the polygonal surface connecting the vertices, the respective vertex colors are usually smoothly interpolated. In this example, different colors are attached to the different corners of a cube. Without support for this feature, the cube won't have any colors.

Standardized Format Support:

3MF: Full support | AutoCAD: Partial support

AutoCAD Notes:

Uses proprietary .dwg format but provides extensive import/export capabilities for industry standards like DXF, STEP, IGES, and other CAD formats for interoperability.

Impact:

Standardization plays a huge role in 3D model formats. With a format being standardized, every application will have a clear way of how to load or store data using this format. This makes it easier to re-use the 3D model across different applications, but also to make sure it will still be accessible and usable after a couple of years.