STEP to STL: Optimising Mesh Sub-Division

For a related note with information on getting started with STL conversions, please see STEP to STL in ReportGen and .io

PDF3D ReportGen and PDF3D.IO development SDK can be used to convert STEP to 3D PDF. In addition, STEP files may also be exported in STL format.

Depending on the application, it may be desirable to mesh triangles to similar sizes. The subdivision algorithm in OC Interface achieves this by including an option to subdivide planar triangles above a size threshold.

This size threshold is calculated based on a user inputted parameter which is multiplied by the diagonal of the bounding box (which applies to the shape being meshed).


Care should be applied in choosing this parameter value as high levels of subdivision may result in very large file sizes.

For example - a STEP file with default linear deflection value which generates 6k triangles.

For this case, enabling default subdivision with factor of 0.05 will generate 100k triangles and 5Mb STL file size. A factor of 0.0025 will create a 1.25GB STL file in about 30 seconds.

Decreasing further to a tolerance factor of 0.001 will create a 7GB STL file with 150 million triangles and take 15 minutes, requiring more than 8Gb in local memory resource.