7 Powerful Tips: Converting PCB designs to 3D STEP
This article describes the best possible methods to convert a 2D Printed Circuit board design (PCB) into a 3D STEP file - which may be used by any 3D CAD SOFTWARE application. It explores the potential pitfalls of converting PCB designs which have plagued 3D software tools for many years. Includes several tips and tricks to help improve the converted 3D STEP files. Lastly promotes using your own 3D Conversion Strategy to ensure accurate conversions with faster performance - resulting in smaller more optimized 3D STEP files.
For PCB designers, a 3D STEP file can be considered as the Gerber data of the 3D Modeling industry. Both 3D STEP and Gerber formats were conceived in the previous century and still widely used almost 50 years later. Both are primarily used for manufacturing purposes and design transfer between various CAD/CAM systems. The 3D STEP format is accepted by all 3D design/modeling software including SolidWorks, Invertor, Pro/Engineer and more. The Gerber format is accepted by all PCB Manufacturing software and CAM tools.
TIP 1: Understand Your 3D Conversion Purpose
Understanding the conversion purpose before generating 3D STEP files - will drastically improve the probability of success, plus you'll save time and money. Here are some of the primary purposes for converting a PCB Design to 3D STEP:
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Simulation / Analysis Generates a compatible 3D STEP file which can be imported into any 3rd party software to perform PCB design analysis features such as: Thermal Electromagnetic, Solvers and other simulations. PCB Enclosure Fit Generates a model of the PCB with Components. Typically used for physical verification such as enclosure fit testing of the final PCB design, etc. Printed Circuit Board Generates a realistic preview of the finished PCB design. Usually for documentation, marketing and/or sales purposes. Other Purpose 3D STEP files are widely used for various purposes such as: simulation, manufacturing, design transfer and documentation. |
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TIP 2: Avoid Common 3D Conversion Pitfalls
Extremely Large 3D STEP File Sizes
3D STEP file sizes are typically larger than all other CAD and EDA formats. This is primarily due to the large number of internal references, geometric redundancies and the formatting of 3D STEP file itself.
Slow Loading into my 3D Modeling applications
No matter how fast a PCB design to 3D STEP file conversion takes, chances are any large 3D STEP files may still takes hours while importing into various 3D Modeling applications.
B-Reps are Usually Responsible
A B-Rep (Boundary Representations) is a solid volume in 3D space, defined by a collection of closed surfaces and optional spatial voids. B-Reps are the most common type of objects used in 3D CAD applications, and require a lot of meta-data that takes up space. B-Reps are the primary culprit for producing exponentially large 3D STEP files that open slowly inside all 3D Modeling applications!
Stacked and Overlapping objects
3D STEP objects (i.e. edges, faces, surfaces) require clean geometries. Most PCB designs consist of stacked layers and objects (especially on the signal/plane layers), which increases the difficulty of completing a 3D conversion from a PCB design.
TIP 3: Output Arcs/Curves whenever possible
All PCB designs have thousands of circular shapes used for pads, vias, etc. Most conversion tools decompose arcs and circles into smaller line segments - by approximating points by degrees. Arc decomposition may be preferred for some purposes, however it will always lead to larger 3D STEP file sizes when converting PCB designs.
Output Arcs/Curves to drastically reduce your 3D STEP file sizes
For example: If approximating a Circle using 5-Degrees will generate a circle with 72 points. Each point contains separate X,Y,Z coordinates that must be stored inside the 3D STEP file, plus the 72 edges (i.e lines) to connect the points. If extruding this simple 2D Circle to become a 3D B-Rep (i.e appearing as a cylinder), 72 more points and edges are also stored for the bottom, plus 74 Solid surfaces (including surfaces for Top/Bottom sides), include storing additional tolerance and attribute information required by the B-Rep - and you've already got a very large 3D STEP file.
TIP 4: Separate 3D STEP file per PCB Layer
Creates a separate 3D STEP file for each PCB layer. Useful to reduce STEP files sizes and allows each file to be imported as separate assemblies in 3D simulation software.
TIP 5: Output as Surfaces and Sweep Later
- Show an example using FreeCAD.
TIP 6: Crop out a section of the PCB Design
- Can be very helpful for purposes involving PCB Simulation and Analysis.
TIP 7: Create your own 3D STEP Conversion Strategy
- Choose STEP Object Types (Based from purpose)
- Increased Tolerance:
- Merge Adjacent Objects:
- Implement various tips and tricks
- Open/Save Configuration files reuse.
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