Introduction

Curvature analysis on CAD (Computer-Aided Design) surfaces is essential for several reasons. 

  • Design Evaluation: Curvature analysis allows engineers and designers to evaluate the quality and feasibility of a design. By analyzing the curvature of surfaces, they can identify potential design flaws, such as areas with excessive curvature or sharp transitions that may cause manufacturing or structural issues. Evaluating the curvature helps ensure that the design meets the desired functional and aesthetic requirements.
  • Manufacturing Considerations: Curvature analysis helps in assessing the manufacturability of a design. Different manufacturing processes, such as molding, machining, or forming, have limitations on the achievable curvature. Analyzing the curvature allows engineers to identify regions that may require complex tooling or additional manufacturing steps. It helps optimize the design for efficient and cost-effective production.
  • Surface Quality and Aesthetics: Curvature analysis plays a crucial role in determining the surface quality and aesthetics of a design. Unwanted variations in curvature can result in undesirable visual effects like ripples, waviness, or distortion. By analyzing the curvature, designers can ensure smooth and visually pleasing surfaces, enhancing the overall product quality and customer satisfaction.
  • Functional Requirements: Curvature analysis is particularly important when designing products that interact with other components or have specific functional requirements. For example, in automotive design, the curvature of car body panels should be carefully analyzed to ensure proper aerodynamics, structural integrity, and compatibility with adjacent parts. Similarly, in consumer products like ergonomic devices or medical equipment, analyzing the curvature helps ensure comfort, usability, and proper interaction with human anatomy.
  • Simulation and Analysis: Curvature information is valuable for performing simulations and analysis of CAD models. For example, in finite element analysis (FEA), curvature data can be used to determine stress concentrations, deformation patterns, and areas prone to failure. Curvature-based analysis also aids in surface fitting, reverse engineering, and geometric comparisons between different CAD models or physical objects.


Overall, curvature analysis on CAD surfaces is crucial for evaluating design feasibility, optimizing manufacturability, achieving desired aesthetics, meeting functional requirements, and performing accurate simulations. It helps ensure that the final product meets quality standards, performs as intended, and can be efficiently manufactured.

Since Blender is now being increasingly used for product/automotive design, there is a need for a fast and robust curvature calculation on subdivision objects. In Blender, the subdivision limit surfaces are still made up of meshes, the curvature calculation depends on the subdivision level.

Thanks to geometry nodes, the following is a pseudo method of displaying curvatuer maps on objects. The above example of a subd object was measured/calibrated in CAD. For most shapes, it works well. Please be reminded that the subdivision level will affect the curvature maps widely. Please cross-check the actual radius of curvature in a CAD application.

Please download the sample Blender file below and use it as a reference object.

Implementation

  • Copy the geometry node "Curvature Analysis" to the object modifier list as the last one.
  • Create a new Color Attribute with Domain as face color
  • .
  • Select the newly created attribute in the Curvature Analysis Geometry Node.
  • To visualize the curvature map, switch to "Attribute" in the viewport shading option.
  • To be able to visualize in EEVEE and Cycles, add a Color attribute, and select the attribute created in step 2.
  • The scale in the Curvature Analysis, controls the scale of curvature display. Red indicates highly curved convex surfaces and blue highly curved concave surfaces. Green indicated relatively flatter areas.
  • Switching from "Linear" to "Constant" in the ColorMap node will threshold the display, aka min or max curvature.

The Curvature Analysis Geometry Node.

Download

Click here to download the blend file.

License:

GPL v3

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