My CAD only exports STL files with triangle shapes. So the first step I do in CAD is to create only polygonal shapes to approximate the curvy shapes. In essence I’m creating my mesh in CAD. It still generates only triangles but in theory they should collapse down to the polygons in my CAD model. Unfortunately, my CAD only exports single precision while Molflow works with higher precision. To get it to collapse to match my CAD model I have to make the tolerance worse and I get leaky facets. While the leaks are less than 0.1% its still annoying. If I build the model in Molflow itself I will not get leaks.
Does anyone have any experience or advice on this? We use SolidWorks.
As I’m not familiar with SolidWorks I can only give some hints:
STL files are by definition triangular, it’s not possible to have polygons with that format, so in this sense your CAD works as expected
Are you approximating curvy shapes by polygons manually to have control over the polygonization? Normally this step is not done: users leave curves as they are and export as STL, which does the polygonization in itself. In all CAD programs there’s a “resolution” option to choose between coarse/fine approximation
As for the lack of precision, check the contents of the STL file. One hack I can think of is to export the model in other units, or even manually scale up by let’s say 100x (which you can undo once the model is in Molflow). This would work for exported coordinates like 0.000011 becoming 0.0010965 for example, but obviously wouldn’t do anything if the coordinates are already in a scientific format like 1.1E-005.
Sorry if I’m posting something you already know, but I found this quick guide about export resolution and their visualized impact. I see that you can choose units in Solidworks. Maybe using millimeters will results in larger numbers, or the opposite, going to meters will add more precision: https://wematter3d.com/exporting-stl-files-for-3d-printing/