PathArray object orientation on Spline

[SmArt]

Hello,
I am new to FreeCAD and I'm trying to understand some of it.

I don't understand how the objects are oriented on one of the paths in the attached file. When following the explanation on
https://wiki.freecadweb.org/Draft%20PathArray

I would say the objects on the B-spline "Bspline_YZ" are not oriented correctly. Can you please explain that or confirm it as bug?

My second question: is there a modifier that would shrink the gaps between objects so that the objects do not exceed the defining path (i.e. fit all objects to this path without the last one going past the path?

Thank you in advance

Best Regards

SmArt

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4 (GitTag)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: 980bf9060e28555fecd9e3462f68ca74007b70f8
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)

[vocx]

...
I would say the objects on the B-spline "Bspline_YZ" are not oriented correctly. Can you please explain that or confirm it as bug?
...

And why would you say that?

[wandererfan]

I don't understand how the objects are oriented on one of the paths in the attached file. When following the explanation on
https://wiki.freecadweb.org/Draft%20PathArray

I would say the objects on the B-spline "Bspline_YZ" are not oriented correctly. Can you please explain that or confirm it as bug?

looks ok from here. What should be different? The origins of your items are on the path and the pointy end is along the tangent of the curve.

My second question: is there a modifier that would shrink the gaps between objects so that the objects do not exceed the defining path (i.e. fit all objects to this path without the last one going past the path?

IIRC, one object goes on the start of the path, another goes on the end of the path and then the space in between is filled with n-2 copies. So you're going to have at least one of the end objects sticking past the path.

[SmArt]

Hello, thanks for the replies.

I would say they are not oriented correctly because the "Spline_XZ" rolls upwards, therefore the N vector points upwards and the N vector should be normal to the side of the triangle. All the other paths have the triangles oriented so that the triangle side is towards the center of rotation. I would say the triangle should be laying flat on the "Spline_XZ".

The pointy end is aligned correctly, the other not-so-pointy-end should be facing right I would say.

Thanks

[wandererfan]

I would say the triangle should be laying flat on the "Spline_XZ".

Sorry for the delay in responding. It should look like this?

BSplineFlatToCenterWorkaround.png (11.41 KiB) Viewed 334 times

A workaround is attached. Fiddling the attachment of the spline sketch rotates the base shape conveniently.

IMO, the error is in DraftGeomUtils.py, #1182 getNorma(). In the case of a BSplineCurve, this routine does not calculate a normal but defaults to Z. I'll see what I can do about submitting a fix.

[wandererfan]

should be fixed after git commit ba7b32e6bc.