solved: Problems with subtractive sweep along a path/edge

[dlouw]

OS: Windows 7
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.18.16093 +17 (Git)
Build type: Release
Branch: (HEAD detached at 0.18.1)
Hash: f7dccfaa909e5b9da26bf50c4a22ccca9bb10c40
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/SouthAfrica (en_ZA)

Hi all, many thanks for freecad!

I am redesigning a crossbow cam and am struggling to add a string groove to one lobe of the cam. I redrew a sketch of the edge (Sketch009) so that the groove (Sketch010) would taper off and not have a sharp edge where the cable makes contact with the cam.

If I select edges, the first part seems to work

SnipImage.JPG (14.47 KiB) Viewed 657 times

But when I add the b-spline edge i get this

snip2.PNG (19.65 KiB) Viewed 657 times

I don't know why because the groove on the string side of the cam seems to work! Any help would be gratefully received. I'm leaving work soon and don't have a PC at home but I look forward to checking replies tomorrow. Thanks in advance.

[papyblaise]

Hello
Maybe it's 2 fatal errors : 1st we can see a gap betwen the path (sketch009) and the profil (sketch010) , we can see the consequence on picture cam1
-2cd you use an B-spline with angle non tangent , that broke the path
Maybe the best way is to use arcs tangent (maybe it's possible)

[dlouw]

Hi Papyblaise, many thanks for the quick reply. I implemented your suggestions and it worked!

[papyblaise]

Ha Ok
but thit morning, just for the fun I redraw the profil of the cam by circle only , so fin as possible of yours , and it's the result

[dlouw]

That is what I did too! But I have found out since the path (b spline or arcs) is not as important as having the path start at, or go through the profile.

Now to print the cam and see if it will work!

Thanks