STEP geometry with inch units imports at wrong scale

Bug Reports
1

After exporting a STEP model file from SolidWorks using inch units, PrePoMax imports the model with inch units but multiplies the dimensions by the conversion factor for mm (25.4).

For example:

  • Geometry is created in SolidWorks and one of the dimensions is 2.0 inches.
  • The geometry is exported in STEP format.
  • A new file is created in PrePoMax with inch units.
  • The STEP file geometry is imported into PrePoMax.
  • The dimension that should be 2.0 inches is 50.8 (2.0 X 25.4) inches on the imported geometry.

After realizing what has happened, the geometry can be scaled back to the proper dimensions.

2

I can confirm this behaviour. It seems that there are many possibilities of how to add units to a .step file. The units can be prescribed for only one dimension, one plane, one part, … That is why the geometry kernel of open-cascade, which is used for geometry processing, automatically converts all units to mm. After that automatic conversion, I would have to figure out the correct unit for each dimension in order to scale it back. Instead a scale function was added to PrePoMax to solve this problem: Geometry → Part → Transform → Scale.