Designers and Parametrics

Can parametrics be designer-friendly? In my 30 years of experience with parametrics, it seems they are typically the domain of CAD engineers and involve a rigid form of manipulation.

Are there examples of user interfaces for parametric drivers of 3D geometry that make them more accessible to the styling or exploratory front end of the design process?

If DSS (SolidWorks) or another CAD provider wanted to really include AI features it would be along these parametric generation topics, much more than generating spindly spirally forms that can only be 3D printed.

Great question though, will keep this in mind. Maybe the sub-D interfaces are better with this, if not ‘true’ parametrics.

There have been efforts to fuse parametric based modelling with freeform modelling. Spaceclaim predates AutoCAD Fusion in this regard.
I’m not saying that allowing a user to switch between the two methodologies is necessarily the last word in UI, as per your question. But maybe a frictionless back and forth (parametric to mesh, smooth and sculpt, mesh back to parametric via robust feature detection, edit, rinse and repeat) might help.
At some point though the user will need to communicate to the computer what defines what, and what is freeform, and which bits can be changed to create variations.
I do find myself wishing the computer would “just know what I mean to do!” when using parametric CAD. As slippyfish above was suggesting, there may be scope for AI /ML techniques to improve the UI here.
Photoshop can now ‘recognise’ a foreground object and remove it. If solidworks recognised that I’ve pierced these two 3d sketches together, it might offer to do the same for the rest and save me a lot of mouse clicks… maybe it might show me variations on what it thinks I want, and let me choose.

I’ve been following and experimenting with the dating life of Blender and Plasticity this year so far. These two NURBS based modelers cater well to the styling side of design as well as provide robust parametrics and, as with Blender’s fidelity, a reasonable expectation of surface smoothness when output as a 3D print.

Even though the title of this video chastises Plasticity a bit, it does a good job of summarizing what I’ve seen so far with robust NURBS parametric modeling. Plasticity has the answer I think you’re looking for.

After 15 years of working with Solidworks, it’s probably the most user-friendly parametric software out there with some advanced features like the Power Surfacing subdivision modeling plug-in (albeit still buggy). I’m trying to see if there are better alternatives out there right now and it seems like Catia and NX UG are pretty good advance modeling alternatives. I’m doing this search because I’m finding not a lot of Chinese companies use Solidworks for some reason. I am realizing the weaknesses of Solidworks now but for most of the work, it’s a good place to start.

You couldn’t give a bit more detail about where you think the parametric CAD UI needs improving, could you?

Blender is an example of a freeform 3D modeller (so suitable for the styling and exploration you mentioned), but some parametric-like functionality can be achieved by using nodes - i.e. parameters you can change and have your model update.

(I haven’t used Blender much myself, your question prompted me to read some Reddit discussions. Blender only works with surfaces, so you may need to bring your model into a solid modeller for bosses, ribs, final check etc)

Not saying it’s the sea change you’re asking for, but Shapr3D is an iPad-first parametric modeler that at least breaks new . I don’t need to pay for another CAD application, but using the Apple Pencil to directly manipulate surfaces and add fillets is nice.

This is like asking an eight year old to talk about dinosaurs!

Buckle up. I’ll try to reduce the impact of my full on obsession into expandable sections, click on the triangle to expand the details. For some of the summarized details, I’ve used chatGPT to assist, I’ve proofread and confirmed and edited the information and conclusions.

Context: Me and my 3D CAD baggage

For the 3D CAD part of my work, I primarily use the “direct modeling” approach, predominantly with Rhino3D, which I have been using extensively over the years. My background includes significant experience with early versions of Pro-E and some usage of SolidWorks. I also have extensive experience with the Unreal Engine for product visualization and simulation, utilizing its node programming capabilities. Additionally, I have used Blender for specialized tasks involving mesh handling and animation.

Before the advent of parametric modeling, I developed and sold a parameter-driven scripting add-on for AutoCAD. This add-on was used for drafting snowboards and generating 2D blueprints for manufacturing, complete with a digitizer tablet icon selection interface.

Currently, I tend to handle both design explorations and the creation of final 3D models myself. This approach allows for immediacy and control over the entire design process.

Slippyfish correctly infers part of my intent in raising this subject. :smirk:

Parametrics”, even as a word it is stiff dry feeling. Put the word in the title, half dread the mods demoting it to the software sub-topic.

Definition of a Parametric Modeler

A parametric modeler is a type of 3D modeling software that allows users to create and modify models using parameters and constraints. These parameters can control various aspects of the model, such as dimensions, angles, and geometric relationships. By adjusting these parameters, users can easily update and modify the model without needing to manually edit each feature.

Key Features of Parametric Modelers

  1. Parameters and Constraints: Users define parameters (e.g., dimensions, angles) and constraints (e.g., parallel, perpendicular) to control the geometry of the model.
  2. Feature-Based Modeling: Models are built using features like extrusions, cuts, and fillets, which can be parametrically controlled and edited.
  3. Design Intent: Captures the design intent by maintaining relationships between features, ensuring changes propagate logically throughout the model.
  4. Associativity: Changes in parameters automatically update related parts of the model, maintaining consistency and reducing the need for repetitive adjustments.
  5. History-Based Modeling: Maintains a history tree of all operations and modifications, allowing users to revisit and edit any step in the modeling process.

Key here is the ability to modify models using parameters and constraints and have the model update downstream of these modifications. There is a symbolic step above the geometry. A number in a dialog box, a slider, a cell in a spreadsheet.

It’s interesting to read the early 2000s postings here on Core and the then status of the design tools and the relatively new integration of parametric computer structure to the design conversation. And comparing that to what has solidified over the ensuing two decades. And the decline in mentions of “parametrics”.

In the process of bringing shape and form to reality, the design industry has generally evolved into well-defined roles. These roles are typically divided into the design determination side and the drafting concretization side. Between these two stages, there is a handover of the design from the “sketcher” to the “CAD person.” The sketcher focuses on the conceptual and creative aspects of the design, while the CAD person handles the technical and detailed drafting required to make the design manufacturable and functional. Generally, there are lots of people that cross the lines.

I appreciate from the above replies that there is a movement to build direct modellers such as Shapr3D, thanks @jkestner and Plasticity @designbreathing that smoothly incorporate parametric type of agents.

2024 me is totally agnostic about modelling engines and software. There are so many excellent solutions and workflows. Regarding specifically Parametric character, these are the chatGPT ratings. I like them both, however in parametrics, it rates them higher than I would.

Blender Rating as Parametric modeling tool: 6.0

Blender is an incredibly versatile tool known primarily for its capabilities in polygonal modeling, sculpting, and animation. However, when it comes to parametric modeling, Blender isn’t traditionally recognized as a strong contender compared to specialized CAD software like Rhino3D, Fusion 360, or SolidWorks.

Here’s a detailed assessment on a scale of 1-10, considering various aspects of Blender’s parametric modeling capabilities:

Strengths of Blender in Parametric Modeling

  1. Flexibility and Customization (7/10): Blender’s modifier stack offers some parametric functionality, allowing users to non-destructively edit models. The recent addition of the Geometry Nodes system enhances its parametric capabilities by allowing procedural generation and modification of geometry.

  2. Integration and Scripting (8/10): Blender’s Python API provides extensive customization and automation possibilities, enabling users to script their own parametric tools and workflows.

  3. User Community and Resources (9/10): Blender has a strong community and abundant resources, including tutorials and add-ons that can extend its parametric modeling functionality.

Weaknesses of Blender in Parametric Modeling

  1. Lack of Native Parametric Features (4/10): Blender lacks the native parametric modeling tools found in dedicated CAD software. Basic parametric controls are present but are not as robust or intuitive as those in specialized programs.

  2. Precision and CAD Integration (5/10): While Blender can handle precise modeling to an extent, it is not inherently designed for the detailed parametric control and engineering specifications required in industrial design and manufacturing.

  3. Usability for Complex Parametric Projects (5/10): For complex parametric design tasks, Blender’s workflow can be cumbersome compared to specialized CAD tools that offer direct parametric modeling features.

Overall Rating

Considering the above aspects, I would rate Blender’s parametric modeling capabilities at 6 out of 10. It provides a basic level of parametric functionality through its modifiers and Geometry Nodes, but it falls short of the comprehensive parametric tools found in dedicated CAD software. Blender excels as a general-purpose 3D modeling and animation tool, but for advanced parametric modeling, more specialized software is generally recommended.


Plasticity Rating as Parametric modeling tool: 6.5

Plasticity, while a relatively new player in the CAD software market, has been making waves with its focus on NURBS modeling and an artist-friendly workflow. Here’s how Plasticity rates as a parametric modeling tool on a scale of 1-10:

Strengths of Plasticity in Parametric Modeling

  1. Ease of Use and Workflow (8/10): Plasticity offers a streamlined, intuitive interface that is especially appealing to users familiar with polygonal modeling software like Blender. The workflow is designed to be efficient, with customizable keybindings and context-sensitive widgets that minimize on-screen clutter【20†source】【24†source】.

  2. Blender Integration (7/10): The Blender Bridge add-on allows seamless data transfer between Plasticity and Blender, enabling real-time previews and streamlined workflows. This integration is particularly beneficial for users who rely on Blender for rendering and additional modeling tasks【25†source】.

  3. NURBS Modeling Capabilities (8/10): Plasticity excels in NURBS modeling, providing precise and scalable models that are ideal for industries requiring detailed, smooth surfaces. The software supports a variety of import and export formats, including STEP, IGES, and Parasolid, which are essential for engineering and design applications【21†source】【25†source】.

Weaknesses of Plasticity in Parametric Modeling

  1. Limited Parametric Features (5/10): While Plasticity supports basic parametric features such as setting absolute dimensions and creating annotations that update automatically, it lacks the comprehensive parametric toolset found in more established CAD software like SolidWorks or Fusion 360. The focus remains more on artistic flexibility rather than precise parametric control【22†source】【24†source】.

  2. Customization and Advanced Features (6/10): Although Plasticity provides some advanced features like customizable radial menus and chordal fillets, it is not as feature-rich in terms of parametric constraints and history-based modeling as traditional CAD software. The development focus is more on improving the user experience and integrating creative workflows rather than expanding parametric capabilities【23†source】【24†source】.

Overall Rating

Considering these aspects, I would rate Plasticity’s parametric modeling capabilities at 6.5 out of 10. It strikes a balance between providing precise NURBS modeling and maintaining an intuitive, artist-friendly interface. However, for users needing robust parametric features and detailed control over model constraints, more specialized CAD tools may be more suitable. Plasticity shines in scenarios where flexibility and ease of use are prioritized over extensive parametric functionality.

I’d give Blender a 3.0 and Plasticity a 4.0 both seem at this point in time to be direct modelers with some parametric features.

I have always believed that front-end user interfaces (UIs) for fully parametric 3D structures would gain popularity for initial form manipulations. The “power of parametric definition” should ideally make complex models easier to interact with. In this envisioned workflow, a fully defined, symbolically controlled parametric model would be built. Then, a “sketcher” could explore and manipulate forms without needing to directly engage with the underlying 3D CAD elements. This separation would allow for more intuitive and creative design exploration, leveraging the parametric model’s flexibility and precision.

However, this seamless integration seems not to have fully materialized yet. Here are some potential reasons:

  1. Early Design Exploration: Design exploration often takes place before full parameters can be defined. During the initial stages, designers need the freedom to experiment without the constraints of predefined parameters.
  2. Different Thinking Processes: The mindsets involved in open-ended design exploration and structured parametric modeling are different. Designers typically engage in a more fluid and creative process, while parametric modeling requires a structured and logical approach. This difference in thinking can create a disconnect. Hence the handoff.
  3. Separation of Roles: In many design workflows, the roles of the “sketcher” and the “CAD person” are distinct. The sketcher focuses on creative exploration, while the CAD person handles the detailed, parametric aspects of the design. This separation can hinder the integration of intuitive form manipulation into parametric modeling.
  4. User Interface Limitations: The user interfaces of parametric CAD programs are often designed for adjustments by engineers. They tend to lack the friendliness and concessions needed to accommodate more casual or creative users. This makes it challenging for designers to manipulate parametric models in an exploratory way.

To bridge this gap, there could be a greater focus on developing project specific UIs that cater to both designers, and on the engineering side, systems to build the symbolic manipulation of the parameters. Touchscreen, voice, specific hardware, etc. These interfaces should enable intuitive exploration of forms while transparently controlling the power and precision of parametric modeling.

Examples of specific parametric modelling tools and their summaries. chatGPT rates these lower for some reason. In my estimation, all of them are 10/10 parametric modellers.

SolidWorks by Dassault Systèmes, Rating as Parametric modeling tool

SolidWorks by Dassault Systèmes is widely recognized as one of the leading parametric modeling tools available, particularly for mechanical and industrial design. Here’s a detailed assessment on a scale of 1-10, considering various aspects of its parametric modeling capabilities:

Strengths of SolidWorks in Parametric Modeling

  1. Comprehensive Parametric Features (10/10): SolidWorks is renowned for its robust parametric modeling capabilities. It allows users to create complex models using a wide range of parametric tools, including constraints, dimensions, and feature-based design. The ability to capture design intent through parametric relationships is one of its strongest features【25†source】 .

  2. Ease of Use and Interface (9/10): SolidWorks offers a user-friendly interface that is intuitive for both beginners and advanced users. Its design tree, feature manager, and integrated tutorials make it accessible while still providing powerful tools for experienced designers【25†source】 .

  3. Integration and Compatibility (10/10): SolidWorks integrates seamlessly with other Dassault Systèmes products and various third-party applications. It supports a wide range of import/export formats and has robust tools for collaboration, simulation, and documentation. This makes it highly versatile and adaptable to different workflows .

  4. Advanced Features and Customization (9/10): SolidWorks includes advanced features such as simulation, motion analysis, and design validation tools. It also supports extensive customization through add-ins and APIs, allowing users to tailor the software to their specific needs .

Weaknesses of SolidWorks in Parametric Modeling

  1. Cost (6/10): SolidWorks is a premium software, and its cost can be a significant barrier for small businesses or individual users. The annual subscription fees can add up, and additional costs may be incurred for certain advanced features or add-ons .

  2. Resource Intensive (7/10): SolidWorks can be resource-intensive, requiring powerful hardware to run smoothly, especially for complex models and simulations. This can be a limitation for users with less capable systems .

Overall Rating

Considering the comprehensive range of parametric features, ease of use, integration capabilities, and advanced tools, I would rate SolidWorks’ parametric modeling capabilities at 9 out of 10. It is a highly capable tool that excels in most areas, making it a top choice for professional designers and engineers in various industries. The main drawbacks are its cost and hardware requirements, but these are often justified by the extensive functionality and support provided.


Summary PTC Creo

PTC’s Creo is another leading CAD software known for its strong parametric modeling capabilities. Here’s a detailed assessment on a scale of 1-10, considering various aspects of Creo’s parametric modeling features:

Strengths of Creo in Parametric Modeling

  1. Robust Parametric Features (10/10): Creo excels in parametric modeling with comprehensive tools for creating complex geometry with precise control. It supports a wide range of parametric and constraint-based modeling techniques, making it ideal for designing intricate parts and assemblies【20†source】【23†source】.

  2. Advanced Simulation and Analysis (9/10): Creo integrates advanced simulation tools, including structural, thermal, and motion analysis. These capabilities allow engineers to validate their designs early in the process, reducing the need for physical prototypes【20†source】【24†source】.

  3. Flexibility and Scalability (9/10): Creo is highly scalable and flexible, making it suitable for both small design projects and large-scale engineering efforts. It offers various modules for different design needs, such as Creo Parametric, Creo Simulate, and Creo Direct, among others【22†source】.

  4. Integration with PLM Systems (10/10): Creo integrates seamlessly with PTC’s Windchill PLM system, enhancing collaboration and data management across the product lifecycle. This integration ensures that all stakeholders have access to up-to-date information and can work efficiently【23†source】.

  5. Customizability and Extensibility (8/10): Creo supports extensive customization and automation through its APIs and add-ons. Users can tailor the software to their specific workflows, enhancing productivity and efficiency【21†source】.

Weaknesses of Creo in Parametric Modeling

  1. Learning Curve (7/10): Creo has a steep learning curve, especially for users new to parametric CAD software. The complexity of its tools and features can be daunting, requiring substantial training and practice to master【21†source】【23†source】.

  2. Cost (7/10): Similar to SolidWorks, Creo is a high-end CAD software with a premium price tag. The cost can be a barrier for small businesses or individual users, particularly when adding advanced modules and simulation tools【22†source】【23†source】.

Overall Rating

Considering the strengths and weaknesses, I would rate Creo’s parametric modeling capabilities at 9 out of 10. Creo is a powerful and versatile tool with comprehensive parametric features, advanced simulation capabilities, and seamless PLM integration. Its main drawbacks are the steep learning curve and high cost, but for professional and industrial applications, Creo remains a top choice.


A simple rating of leading parametric CAD tools on a scale of 1-10:

Parametric Modeling Tool Ratings

  1. SolidWorks: 9/10

    • Comprehensive parametric features, user-friendly interface, and extensive toolset for design, simulation, and documentation.
  2. PTC Creo: 9/10

    • Advanced parametric modeling, robust simulation tools, and seamless PLM integration.
  3. Autodesk Fusion 360: 8/10

    • Combines CAD, CAM, and CAE tools with strong collaboration features and ease of use.
  4. Siemens NX: 9/10

    • Powerful parametric modeling, simulation, and manufacturing capabilities suitable for complex designs.
  5. CATIA: 9/10

    • Handles complex and large-scale models with advanced surface and shape design capabilities.
  6. Autodesk Inventor: 8/10

    • Professional-grade 3D mechanical design, documentation, and product simulation tools.
  7. Onshape: 7/10

    • Cloud-based platform with powerful parametric modeling and real-time collaboration.
  8. Solid Edge: 8/10

    • Synchronous technology combining direct modeling with parametric design flexibility.
  9. Rhino with Grasshopper: 7/10

    • Freeform surface modeling enhanced with script-based parametric control through Grasshopper.
  10. FreeCAD: 6/10

    • Open-source parametric modeling with support for various file formats, suitable for mechanical engineering and product design.


I believe we are on the verge of the next evolution in form exploration and realization. AI engines are now capable of generating very rough mesh models, they look at form the same way they look at words, in a very general statistical way. The necessary tools for controlling actual geometry, such as NURBS, are already in place. This potential interaction with AI and defined geometry parallels the traditional interaction between the designer/sketcher and the geometry.

Currently, I am working on this and am approaching the implementation phase. My original intent in posting this question was to inquire about existing bridges that connect designer explorations with engineering processes for serial object production. These bridges would go beyond simple configurators, delving deeper into the geometry to facilitate transitions from design to manufacturing.

The input of programs such as Shapr3D for the iPad making modeling more accessible are welcome, amazing tools. Thanks for commenting and reading this far!


This is fascinating, thank you for the exposition.