Attaching B-Spline to circle

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MRx
Posts: 65
Joined: Wed Jul 08, 2020 5:59 am
Location: Tainan / Taiwan

Attaching B-Spline to circle

Postby MRx » Mon Apr 19, 2021 9:28 pm

Hi,

is there any way to attach a b-spline to a circle / circular surface?
b-spline_circle.png
b-spline_circle.png (3.04 KiB) Viewed 233 times
I'd like to attach this b-spline, and sweep a pipe over it, however I have no idea how it can be attached.
chrisb
Posts: 34174
Joined: Tue Mar 17, 2015 9:14 am

Re: Attaching B-Spline to circle

Postby chrisb » Mon Apr 19, 2021 9:44 pm

The image shows two curves, and the are not connected. You cannot sweep along those two.

To attach a sketch to a spline or any other thing, click MapMode, then click the button occurring at the right. Select the spline and use mode Frenet NB.
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MRx
Posts: 65
Joined: Wed Jul 08, 2020 5:59 am
Location: Tainan / Taiwan

Re: Attaching B-Spline to circle

Postby MRx » Mon Apr 19, 2021 10:18 pm

I attach a better sample. I couldn't figure out how to attach to that surface.
bspline_curve2.png
bspline_curve2.png (21.72 KiB) Viewed 213 times
Attachments
bspline.FCStd
(15.66 KiB) Downloaded 5 times
Bance
Posts: 1813
Joined: Wed Feb 11, 2015 3:00 pm
Location: London

Re: Attaching B-Spline to circle

Postby Bance » Mon Apr 19, 2021 11:37 pm

Which ever mode you choose the spline will attach at its centre point, because that is where you have positioned it.

In other words, the spline has been drawn around the origin which is the point that attachment uses to anchor the sketch to its destination.

See Basic_Attachment_Tutorial for a more in depth explanation.
MRx
Posts: 65
Joined: Wed Jul 08, 2020 5:59 am
Location: Tainan / Taiwan

Re: Attaching B-Spline to circle

Postby MRx » Tue Apr 20, 2021 2:16 am

Sorry I don't understand that, I tried and it will always attach to the straight square edge of the drawn circle.

I also found Map a sketch on a surface in the curves workbench, but it gives me:
12:14:57 Failed to get the face support of the sketch

The sketch should be mapped onto the round surface of the object.

Following is what I actually want to draw (and print):
1604_2.png
1604_2.png (190.78 KiB) Viewed 176 times
MRx
Posts: 65
Joined: Wed Jul 08, 2020 5:59 am
Location: Tainan / Taiwan

Re: Attaching B-Spline to circle

Postby MRx » Tue Apr 20, 2021 4:47 am

Seems like I was able to do that but super complicated...

Can anyone advise a better way how to get that done?
bspline_mapped.png
bspline_mapped.png (44.79 KiB) Viewed 154 times
I have attached the project...

I was not able to map the b-spline directly to the curved surface, I had to create an object and intersected the curve. I used the guides generated by the intersection to swipe along that path for removing the half-circle.
Attachments
bspline.FCStd
(401.49 KiB) Downloaded 3 times
MRx
Posts: 65
Joined: Wed Jul 08, 2020 5:59 am
Location: Tainan / Taiwan

Re: Attaching B-Spline to circle

Postby MRx » Tue Apr 20, 2021 6:43 am

ok I think I have it, I can create a helix and apply that one.
I just did not see the primitive like that before.

Applying sketches to surfaces seems to be challenging, on the other side I could probably still get away with b-splines, just by making a very tiny closed object and applying that one; just an open object doesn't seem to work.
Bance
Posts: 1813
Joined: Wed Feb 11, 2015 3:00 pm
Location: London

Re: Attaching B-Spline to circle

Postby Bance » Tue Apr 20, 2021 7:05 am

It's good that you have found a solution. Your title is slightly misleading, in FC attaching is a particular way of doing things.

See Part_Attachment

What you are trying to do here, is mapping to a face. The difference is subtle, but there it is.