How to convert OBJ
to Parasolid?

The OBJ format is a popular and widely used file format for representing 3D geometry. It was initially developed by Wavefront Technologies for their Advanced Visualizer software. OBJ files store information about the vertices, faces, texture coordinates, normals, and material properties of a 3D model.

This format supports the representation of polygonal geometry, making it versatile for a wide range of applications. OBJ files are widely supported by various 3D modeling, animation, and rendering software, making it easy to share and exchange 3D models across different platforms and workflows.

Support of OBJ files in CAD Exchanger

CAD Exchanger can import files with external .mtl (material library) files, files with both multiple and single parts, and export files. Such support includes:

• polygonal representations;
• colors, materials, textures.

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Pros of the format

Universality

One of the key advantages of this format is its widespread compatibility. OBJ files can be imported and exported by a vast number of 3D modeling, animation, and rendering software applications. This broad support allows for seamless collaboration between different software packages, making it easier to share 3D models across various platforms and workflows. Whether you're working with industry-standard software or niche tools, chances are high that they will support the OBJ format.

Simplicity

The OBJ format is known for its simplicity and ease of use. OBJ files are plain text files, making them human-readable and easily editable. This simplicity makes it straightforward to manually modify or create OBJ files using a basic text editor if needed. Additionally, the file structure of OBJ is relatively straightforward, consisting of vertices, faces, and associated information. This simplicity makes it accessible for beginners and allows for quick understanding and integration with other software pipelines.

Cons of the format

Limited Geometry Support

This format has some limitations when it comes to representing complex geometry. OBJ is actually a polygonal format, so B-Rep is not supported as a class, neither for a simple cylinder nor for super-complex geometry. As a result, OBJ is not suitable when there is a need for B-Rep, and not polygonal meshes. This can be a disadvantage when working with models that require precise curved surfaces or complex mathematical representations.

Lack of Animation and Rigging Data

Another drawback of the OBJ format is that it does not inherently support animation or rigging data. OBJ files primarily focus on static 3D geometry representation and lack the ability to store information related to skeletal animation, rigging, and dynamic simulations. It also lacks several features like support for lights, LOD settings, and advanced materials. This makes it less suitable for complex animated scenes or character animations that require bone structures, joint deformations, or motion data.

FAQ

Is OBJ format specification publicly available?

Yes, it is. The OBJ file format specification defines the structure and organization of OBJ files. OBJ files begin with a list of vertex data, which consists of coordinates (X, Y, Z) that define the geometry of the 3D model. Texture coordinates (U, V) can also be included to map textures onto the model's surfaces. Normal vectors (X, Y, Z) define the orientation of the surfaces.

Faces are defined using indices that reference the previously defined vertices, texture coordinates, and normals. Groups and smoothing can be specified to organize the model's faces and define the shading and smoothness of adjacent faces. Additionally, OBJ files can reference material libraries (MTL files) that define properties like color, reflection, and transparency for the model's surfaces.

What are the typical .obj file extensions?

The OBJ file format is usually associated with two file extensions: .obj and .mtl.

.obj is the primary extension for OBJ files. It represents the 3D geometry data, including vertex coordinates, texture coordinates, normal vectors, and face definitions. The .obj file contains the essential information required to represent the shape and structure of the 3D model.

.mtl is a companion file to the OBJ format. It contains information about the material properties applied to the surfaces of the 3D model, such as color, reflectivity, transparency, and textures. The .mtl file is referenced by the OBJ file to assign materials to different parts of the model.

How to open a .obj file?

To open this file, you will need a compatible software application, for example, CAD Exchanger Lab. Launch the software and navigate to the 'New file' option. Browse your computer's directories and locate the .obj file you want to open. Then select it and click "Open". Once the import process is complete, the .obj file should be loaded into the software, allowing you to view and interact with the 3D model and associated data.

History of the OBJ format

The OBJ file format has a rich history in the field of computer graphics. It was originally developed by Wavefront Technologies, a company known for its pioneering work in 3D computer graphics and animation software. The OBJ format was first introduced in the late 1980s as part of Wavefront's Advanced Visualizer software, which was widely used in the film and entertainment industry.

Wavefront designed the OBJ format to provide a standard way to exchange 3D models between different software applications. It aimed to address the interoperability challenges that arose due to the diverse range of 3D modeling and animation software available at the time.

As the OBJ format gained popularity, it became widely adopted by the computer graphics community. Its simplicity, versatility, and support for geometry, texture, and material data made it a favored choice for sharing 3D models across various platforms and software packages.

The OBJ format has been embraced by numerous 3D software applications, making it a de facto standard for exchanging 3D models. Despite the emergence of newer formats, OBJ remains widely used and supported due to its long-standing history, compatibility, and ease of integration into different workflows. Today, the OBJ format continues to play a significant role in the world of 3D computer graphics.

Parasolid file format is native for Parasolid geometrical kernel, a widely used 3D geometric modeling kernel developed by Siemens PLM Software. This kernel provides a set of advanced tools and algorithms for creating, editing, and analyzing complex models. Like any kernel, Parasolid also has a persistence format known as Parasolid-XT. The Parasolid format refers to the file format used to store and exchange 3D geometry data created using Parasolid.

Support of Parasolid files in CAD Exchanger

CAD Exchanger can import files starting from v0.15 and up to v35 and export files from v12 to v35. Such support includes:

• B-Rep representations;
• assembly structure;
• names;
• user-defined properties;
• colors;
• layers.

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Pros of the format

Kernel nature

The primary advantage of Parasolid-XT lies in its kernel-based architecture. When you need to import data into CAD software running on the Parasolid kernel, opting for this format is a wise decision. As a kernel format, Parasolid-XT excels in its handling of B-Rep geometry, demonstrating exceptional proficiency in storing intricate B-Rep models encompassing solids, sheets, wireframes, mixed components, and even non-manifold topologies.

A notable advantage over the ACIS-SAT format is its capacity to represent the model hierarchy, albeit with some limitations (parts and bodies are somewhat synonymous). Nevertheless, in essence, the conversion to Parasolid-XT has the potential to preserve your part-assembly hierarchies, adding to its appeal as a preferred choice.

Representation of hybrid models

Another notable capability is the endorsement of hybrid models, specifically those in which a single logical component encompasses both B-Rep and mesh geometry. While this scenario currently represents a relatively small portion of real-world data exchange, it's gaining popularity. Consequently, the Parasolid kernel has been actively advancing to embrace these models, with the most recent iterations of the Parasolid-XT format designed to handle them.

Cons of the format

Proprietary nature

Parasolid is a proprietary format owned and developed by Siemens PLM Software. This means that the specifications of the format are not publicly available, and only licensed software developers can fully access and utilize the features of Parasolid. While many CAD software applications support the import and export of Parasolid files, the lack of public specifications can limit the ability to develop custom tools or work with the format outside of the licensed software ecosystem.

The lack of extensive metadata and visual attributes support

Parasolid-XT offers some support for metadata and visual attributes, including the ability to name entities, assign colors to shapes, utilize layers, and user-defined properties as key-value pairs. However, if you're dealing with multi-body parts, PMI, or advanced metadata, it might be more beneficial to consider using alternative formats like STEP or JT. These formats provide more extensive support for those specific requirements.

FAQ

What are the benefits of using Parasolid format?

The Parasolid format offers exceptional interoperability, and precise B-rep modeling ensures high geometric accuracy, making it suitable for complex engineering and design tasks. Its wide industry adoption makes it a trusted and standardized format, ensuring compatibility and long-term support.

Which industries use Parasolid format?

The Parasolid format finds extensive use in various industries due to its versatility and precision. Industries such as aerospace, automotive, manufacturing, consumer electronics, and medical devices all rely on Parasolid for 3D modeling and design. Its broad adoption across these sectors facilitates the development of everything from aircraft components and automotive designs to medical implants.

What are the primary Parasolid file extensions?

In Parasolid, two primary file extensions are commonly used. The first one is .x_t (Parasolid Text), which represents a text-based format. It stores 3D geometric data in a text format, allowing for easy interoperability between different CAD systems. The second extension is .x_b (Parasolid Binary), which represents a binary format. .x_b files contain the same geometric information as .x_t files but in a more compact and faster-to-process binary format.

History of Parasolid format

The Parasolid format, as a file format for storing 3D geometry, has its own history. Developed by Shape Data Limited in the 1980s, the Parasolid format was designed to enable the exchange of 3D solid models between different CAD systems.

In 1996, the company was acquired by Unigraphics Solutions Inc., which eventually became part of Siemens PLM Software. Since then, Parasolid has continued to evolve and adapt, keeping up with the ever-changing demands of the CAD industry.

With its powerful capabilities and efficient representation of 3D geometry, Parasolid quickly became a standard format for CAD software developers. Its widespread acceptance can be attributed to its seamless interoperability. Many leading CAD software applications, including Siemens NX, Solid Edge, and SolidWorks, incorporate Parasolid as their underlying kernel, allowing users to create, modify, and exchange complex 3D models with ease.

Over the years, Parasolid has played a vital role in various industries, such as automotive, aerospace, and consumer goods. Its precision and accuracy have made it an indispensable tool for designers and engineers, enabling them to tackle intricate designs and perform detailed analyses. Today, Parasolid remains a cornerstone in the CAD landscape, empowering professionals to bring their creative ideas to life in the virtual world.