Exported bodies are bigger in size than the original file

[Mannshoch]

I tested the "Export selected Items" feature (source STEP 242 destination also STEP) and had the strange effect, that the resulting size double than the original File.

What could be the cause of this?

Source File Schema (Inventor):

ISO-10303-21;
HEADER;
FILE_DESCRIPTION(
 ('',
'CAx-IF Rec.Pracs.---Representation and Presentation of Product Manufa
cturing Information (PMI)---4.0---2014-10-13'),
 '2;1');
FILE_SCHEMA (('AP242_MANAGED_MODEL_BASED_3D_ENGINEERING_MIM_LF { 1 0 10303 442 1 1 4 }'));
ENDSEC;
DATA;

Dest File Header (Mayo 0.9):

ISO-10303-21;
HEADER;
FILE_DESCRIPTION(('OpenCascade Model'),'2;1');
FILE_NAME('Open CASCADE Shape Model','2025-03-24T16:34:40',(''),(''),
  'Open CASCADE STEP processor 7.8','Open CASCADE 7.7','Unknown');
FILE_SCHEMA(('AUTOMOTIVE_DESIGN { 1 0 10303 214 1 1 1 1 }'));
ENDSEC;
DATA;

Goal was to reduce the Data not to increase it. [edit] Tested also with v0.9.0

[Mannshoch]

Could it be that in the exported file each occurrence of a file is saved separately instead of saving the body that is used multiple times only once?

[HuguesDelorme]

Try to set the STEP option "Write Parametric Curves" to OFF:

I've tried with this file(not AP242 but AP214): https://grabcad.com/library/raspberry-pi-3-reference-design-model-b-rpi-raspberrypi-raspberry-pi-1

Original size: 26MB Export size: 15.1MB (schema: AP242_DIS, write_parametric_curves: OFF) Export size: 36.3MB (schema: AP242_DIS, write_parametric_curves: ON)

[Mannshoch]

What use does this parametric curves have? Do I lose some important data?