Sketcher tutorial

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abdullah
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Joined: Sun May 04, 2014 3:16 pm

Re: Sketcher tutorial

Postby abdullah » Mon Jan 07, 2019 10:03 am

robcad wrote:
Mon Dec 31, 2018 7:22 pm
And here is how it does not work under certain conditions.
chrisb wrote:
Thu Jan 03, 2019 1:28 am
I have no idea what's going on, I haven't ever seen this error message. Abdullah, can you help?
Hi there! Sorry for the long absence.

I think the problem might be the "rendering order" in the "Edit Controls".

The error message is telling you that the point that you are selecting is not connected to an edge. This is because what is selected is the center of the endpole, which is at the same location as the endpoint of the bspline.

When there are co-located points, the point that is selected, generally depends on which object was created first, and thus is rendered first, unless one of the specific rules of the "rendering order" applies.

You may remember that the original B-Spline creation introduced the circles of the poles AFTER the B-Spline. Then you always had to use the work-around of using the Element's widget. Then the creation was rewritten some six months ago to introduce the circles of the poles BEFORE the B-Spline. This allowed that, with the "normal" rendering order, the endpoints are selected and it is way more usable. However, if one changes the order to "construction" geometry first, then you will select the center of the construction circle of the pole.
chrisb
Posts: 14103
Joined: Tue Mar 17, 2015 9:14 am

Re: Sketcher tutorial

Postby chrisb » Mon Jan 07, 2019 6:29 pm

abdullah wrote:
Mon Jan 07, 2019 10:03 am
I think the problem might be the "rendering order" in the "Edit Controls".
Thanks for this excellent explanation, I'm glad that nothing is broken. Alas, it means I have to add this to my tutorial.
abdullah
Posts: 2822
Joined: Sun May 04, 2014 3:16 pm

Re: Sketcher tutorial

Postby abdullah » Tue Jan 08, 2019 12:46 pm

chrisb wrote:
Mon Jan 07, 2019 6:29 pm
abdullah wrote:
Mon Jan 07, 2019 10:03 am
I think the problem might be the "rendering order" in the "Edit Controls".
Thanks for this excellent explanation, I'm glad that nothing is broken. Alas, it means I have to add this to my tutorial.
Welcome! I use each opportunity to give you extra work :mrgreen: :lol: :lol: :lol:
robcad
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Location: Berlin

Re: Sketcher tutorial

Postby robcad » Tue Jan 08, 2019 8:37 pm

abdullah wrote:
Mon Jan 07, 2019 10:03 am
I think the problem might be the "rendering order" in the "Edit Controls".
Thanks, yes this is the "problem".
B-Spline_Exercise_16 + Rendering Order.gif
B-Spline_Exercise_16 + Rendering Order.gif (413.47 KiB) Viewed 430 times
B-Spline_Exercise_16.fcstd
(6.12 KiB) Downloaded 4 times
(1) What is the default setting of "Rendering order"?
(2) Is there an other way to have a choice between Vertex1 and Vertex6?
(3) Is there a way to see that Vertex6 is the endpoint of the spline?
chrisb
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Joined: Tue Mar 17, 2015 9:14 am

Re: Sketcher tutorial

Postby chrisb » Tue Jan 08, 2019 10:14 pm

robcad wrote:
Tue Jan 08, 2019 8:37 pm
(2) Is there an other way to have a choice between Vertex1 and Vertex6?
(3) Is there a way to see that Vertex6 is the endpoint of the spline?
Good to see that it works.
In the Elements section in the Sketcher panel you can switch the type from "Edge" to "Starting point" or "End point". When you now select an element in the list (not in 3D view!) than the corresponding start point or endpoint is selected.
abdullah
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Joined: Sun May 04, 2014 3:16 pm

Re: Sketcher tutorial

Postby abdullah » Wed Jan 09, 2019 12:39 pm

robcad wrote:
Tue Jan 08, 2019 8:37 pm
(1) What is the default setting of "Rendering order"?
(2) Is there an other way to have a choice between Vertex1 and Vertex6?
(3) Is there a way to see that Vertex6 is the endpoint of the spline?
The current FC daily from the PPA:
OS: Ubuntu 18.04.1 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15592 (Git)
Build type: Release
Branch: master
Hash: a7c0f4bc5b62ec304a5855796ca3d10a42c7a46e
Python version: 2.7.15rc1
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
"Silently" dies when I try to load your file (and not only yours):
Program received signal SIGSEGV, Segmentation fault.
#0 /lib/x86_64-linux-gnu/libc.so.6(+0x3ef20) [0x7fd388302f20]
corrupted double-linked list
when trying to load one file, so I cannot check my answers:

(1) Normal, Construction, External

(2) Element's widget. Check the "extended naming" checkbox if unchecked.

(3) Iterate one Element's "edge","startpoint","endpoint","center" by pressing 'z' while you hover the element in the elements widget. The preselection will mark the part of the element in yellow on the 3D view. Alternatively, you may use the selection drop box as Chris says.
abdullah
Posts: 2822
Joined: Sun May 04, 2014 3:16 pm

Re: Sketcher tutorial

Postby abdullah » Wed Jan 09, 2019 1:04 pm

The crash should be solved, as this self-compiled version does not crash:
OS: Ubuntu 18.04.1 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15596 +1 (Git)
Build type: DEBUG
Branch: _geometry_extension_
Hash: ac7b387f781fff45163c13b5543cbc108bc40ebc
Python version: 3.6.7
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
robcad
Posts: 14
Joined: Mon Feb 12, 2018 7:20 pm
Location: Berlin

Re: Sketcher tutorial

Postby robcad » Wed Jan 09, 2019 7:06 pm

robcad wrote:
Tue Jan 08, 2019 8:37 pm
(2) Is there an other way to have a choice between Vertex1 and Vertex6?
(3) Is there a way to see that Vertex6 is the endpoint of the spline?
abdullah wrote:
Wed Jan 09, 2019 12:39 pm
(2) Element's widget. Check the "extended naming" checkbox if unchecked.
(3) Iterate one Element's "edge","startpoint","endpoint","center" by pressing 'z' while you hover the element in the elements widget. The preselection will mark the part of the element in yellow on the 3D view. Alternatively, you may use the selection drop box as Chris says.
Using "Z"-Key while hover the element:
B-Spline_Exercise_16 + Z-Key.gif
B-Spline_Exercise_16 + Z-Key.gif (371.45 KiB) Viewed 358 times
B-Spline_Exercise_16.fcstd
(6.13 KiB) Downloaded 3 times
Nice way to work. Thanks.
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jrdrukin
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Location: Hawthorne CA
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Re: Sketcher tutorial

Postby jrdrukin » Fri Jan 18, 2019 4:01 pm

chrisb,
I just spent few minutes re-reading it.
Every time I read your Sketcher Tutorial I learn and/or reinforce
important concepts necessary for 3d modeling and FC.
Thank you very much for your considerable time and effort!
Your work is greatly appreciated! :)
Jerry/jrdrukin
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jrdrukin
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Re: Sketcher tutorial

Postby jrdrukin » Fri Jan 18, 2019 4:19 pm

chrisb,
Maybe add DOF's for the conics and b-splines to your table on pp.74?