Import of STEP format Geometry Re-scales Units

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Import of STEP format Geometry Re-scales Units

randress
I created two cubic "box"es using Autodesk Fusion 360. One is 1x1x1 and the other is 1000x1000x1000. The default and document units on Fusion 360 were set to meters (m).

When I import them in FEATool->Geometry->Import Geometry->STEP Format, the dimension of the block displayed is 1000 times the size specified in the file

For the 1 unit cube ...

Box_m_v1.step

... relevant lines show a 1 unit cube:
#153=CARTESIAN_POINT('',(0.,0.,0.));
#154=CARTESIAN_POINT('Origin',(0.5,1.,0.5));
#155=CARTESIAN_POINT('',(0.,1.,1.));
#156=CARTESIAN_POINT('',(1.,1.,1.));
#157=CARTESIAN_POINT('',(0.5,1.,1.));
#158=CARTESIAN_POINT('',(1.,1.,0.));
#159=CARTESIAN_POINT('',(1.,1.,0.5));
#160=CARTESIAN_POINT('',(0.,1.,0.));
#161=CARTESIAN_POINT('',(0.5,1.,0.));
#162=CARTESIAN_POINT('',(0.,1.,0.5));
#163=CARTESIAN_POINT('Origin',(0.5,0.,0.5));
#164=CARTESIAN_POINT('',(1.,0.,1.));
#165=CARTESIAN_POINT('',(0.,0.,1.));
#166=CARTESIAN_POINT('',(0.5,0.,1.));
#167=CARTESIAN_POINT('',(0.,0.,0.));
#168=CARTESIAN_POINT('',(0.,0.,0.5));
#169=CARTESIAN_POINT('',(1.,0.,0.));
#170=CARTESIAN_POINT('',(0.5,0.,0.));
#171=CARTESIAN_POINT('',(1.,0.,0.5));
#172=CARTESIAN_POINT('Origin',(0.,0.5,0.5));
#173=CARTESIAN_POINT('',(0.,0.5,0.));
#174=CARTESIAN_POINT('',(0.,0.5,1.));
#175=CARTESIAN_POINT('Origin',(0.5,0.5,0.));
#176=CARTESIAN_POINT('',(1.,0.5,0.));
#177=CARTESIAN_POINT('Origin',(1.,0.5,0.5));
#178=CARTESIAN_POINT('',(1.,0.5,1.));
#179=CARTESIAN_POINT('Origin',(0.5,0.5,1.));
But the block displayed is not 1x1x1 but 1000x1000x1000:



And for the 1000 unit cube ...

1000mBox.step

... relevant lines show 1000 unit cube.
#154=CARTESIAN_POINT('Origin',(-499.95,1000.,-499.95));
#155=CARTESIAN_POINT('',(0.05,1000.,-999.95));
#156=CARTESIAN_POINT('',(-999.95,1000.,-999.95));
#157=CARTESIAN_POINT('',(-499.95,1000.,-999.95));
#158=CARTESIAN_POINT('',(-999.95,1000.,0.05));
#159=CARTESIAN_POINT('',(-999.95,1000.,-499.95));
#160=CARTESIAN_POINT('',(0.05,1000.,0.05));
#161=CARTESIAN_POINT('',(-499.95,1000.,0.05));
#162=CARTESIAN_POINT('',(0.05,1000.,-499.95));
#163=CARTESIAN_POINT('Origin',(-499.95,0.,-499.95));
#164=CARTESIAN_POINT('',(-999.95,0.,-999.95));
#165=CARTESIAN_POINT('',(0.05,0.,-999.95));
#166=CARTESIAN_POINT('',(-499.95,0.,-999.95));
#167=CARTESIAN_POINT('',(0.05,0.,0.05));
#168=CARTESIAN_POINT('',(0.05,0.,-499.95));
#169=CARTESIAN_POINT('',(-999.95,0.,0.05));
#170=CARTESIAN_POINT('',(-499.95,0.,0.05));
#171=CARTESIAN_POINT('',(-999.95,0.,-499.95));
#172=CARTESIAN_POINT('Origin',(0.05,500.,-499.95));
#173=CARTESIAN_POINT('',(0.05,500.,0.05));
#174=CARTESIAN_POINT('',(0.05,500.,-999.95));
#175=CARTESIAN_POINT('Origin',(-499.95,500.,0.05));
#176=CARTESIAN_POINT('',(-999.95,500.,0.05));
#177=CARTESIAN_POINT('Origin',(-999.95,500.,-499.95));
#178=CARTESIAN_POINT('',(-999.95,500.,-999.95));
#179=CARTESIAN_POINT('Origin',(-499.95,500.,-999.95));
But the block displayed has units that are 1000 times that (10 x 10^5):



What am I missing?

Kind regards,
Randal
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Re: Import of STEP format Geometry Re-scales Units

Precise Simulation
Administrator
The geometry engine uses "mm" units internally (as 1 m = 1000 mm), and currently convert STEP/IGES files if given in other units. You can compensate by scaling before/after import or modeling/exporting in "mm" from other CAD software.
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Re: Import of STEP format Geometry Re-scales Units

randress
Precise Simulation wrote
The geometry engine uses "mm" units internally (as 1 m = 1000 mm), and currently convert STEP/IGES files if given in other units. You can compensate by scaling before/after import or modeling/exporting in "mm" from other CAD software.
Hmmm...well, that sounds simple enough :-)  

... but what about tolerances? are there not absolute-value tolerances such as the 1e-5 I have noticed?  does it matter where I do the pre/post scaling as far as the effect on tolerances used for intersection, etc.? (I am speaking more than I know here....just trying to express my concern.)

Kind regards,
-Randal