Refine does not remove edges

[kisolre]

I was trying to mirror whole body inside itself by using scaled to -1 clone and fusing to original. It lookas like it works but then I tryed to refine the features and it did not remove internal edges. Any idea why?
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RefineEr.JPG (69.88 KiB) Viewed 392 times

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OS: Windows 8.1 (6.3)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.19678 (Git)
Build type: Release
Branch: master
Hash: b34f0aef34297c5eda6fb5cf1bbc1b43d452a31d
Python version: 3.6.8
Qt version: 5.12.1
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Bulgarian/Bulgaria (bg_BG)

[UR_]

Different types of surfaces can't be "refined" together.

Screenshot 005.png (11.95 KiB) Viewed 385 times

Screenshot 006.png (15.88 KiB) Viewed 385 times

[kisolre]

Why are they different? Did the clone convert that Plane to BSplineSurface? I tried just displacing the clone and it is properly refined. But any scale <>1 causes such conversion. Is it OCC thing and is there a way to avoid it?
How do you inspect the faces like in your scfreenshots?

[UR_]

How do you inspect the faces like in your scfreenshots?

Done with "Info" tool from CurvesWB.

Screenshot 007.png (22.12 KiB) Viewed 361 times

[openBrain]

Did the clone convert that Plane to BSplineSurface?

I think so but don't know why. Link seems to not suffer this problem when scaled.

[wmayer]

Did the clone convert that Plane to BSplineSurface?

I think so but don't know why. Link seems to not suffer this problem when scaled.

OCCT has two transformation methods: a geometric transformation and a transformation that changes the placement

For the geometric transformation OCCT has the habit to convert all geometries into B-Spline curves/surfaces. It does so even if the transformation is a simple translation.

For the latter OCCT doesn't touch the underlying geometry. But for scaling operations (especially when values are different in the local X,Y,Z axes) you must use the geometric variant.