How to use M function in polyline

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chrisb
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Re: How to use M function in polyline

Postby chrisb » Thu May 10, 2018 9:46 pm

No problems here on Linux. Must be a permission issue on your side.
Rod
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Re: How to use M function in polyline

Postby Rod » Fri May 11, 2018 7:29 am

chrisb wrote:
Thu May 10, 2018 9:46 pm
No problems here on Linux. Must be a permission issue on your side.
Hi Chris,

you have been very helpful in my threads and here.

I have not used the 'M' key before reading this thread. Diabolical little thing it is... :D

Just so you can pull more hair out :shock: I tried cycling through your 6 'M' options and could only get it to do the first 5 before it returned me to normal line mode. Not that I'm really worried, just thought I'd say.
bejant wrote:
Thu May 10, 2018 12:56 pm
Will try this exercise myself...although embarressingly :oops: I must ask where is the exercise...checked FC homepage exercises, the forum and wiki exercises and for bejant on youtube (lots of stuff but not exercise 5 using M key).

Edit: Never mind...I think I will pull my own hair out instead. Just found it I think as a footnote in bejant's post previous page. :oops: :oops: :oops:

Edit: Lots of interesting exercises there bejant. Did the sketch to rotation in about 8 minutes, no vertice issues etc. Mind, I did not slavishly follow the dimensions, but did put in all the fillets. Will finish the rest of the exercise later.

Would be nice if the arcs could give a 90 degree/45 degree preset indicator like lines have the horizontal or vertical helper. Not a biggy.
chrisb
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Re: How to use M function in polyline

Postby chrisb » Fri May 11, 2018 9:43 am

Rod wrote:
Fri May 11, 2018 7:29 am
Hi Chris,

you have been very helpful in my threads and here.
You're welcome
Just so you can pull more hair out :shock: I tried cycling through your 6 'M' options and could only get it to do the first 5 before it returned me to normal line mode. Not that I'm really worried, just thought I'd say.
Thanks for pointing it out, copy+paste+delete+insert made it simply wrong. Can you recheck please?
Rod
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Re: How to use M function in polyline

Postby Rod » Fri May 11, 2018 11:47 am

chrisb wrote:
Fri May 11, 2018 9:43 am
Rod wrote:
Fri May 11, 2018 7:29 am
Can you recheck please?

Correction to previous - 6 instead of 7 (not 5 instead of 6).

Sorry, you instructions were entirely correct. My bad. 7 is not a stroke of the 'M' key. So it is 6 strokes of 'M' over 7 points of instruction.

Excluding the first line - 6 stokes for cycle - see gif.
M key.gif
M key.gif (212.1 KiB) Viewed 275 times
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bejant
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Re: How to use M function in polyline

Postby bejant » Fri May 11, 2018 3:42 pm

FC-Architecter wrote:
Thu May 10, 2018 6:21 pm
I deleted Equality Constraint 43.
...snip...
Sorry, my last description of what to do wasn't very good so I will try again.
  • With Constraint 43 existing, apply a Horizontal Constraint to the upper horizontal line segment of the inside of the pulley cheek.
  • Sketcher Solver gives a message that there are now redundant constraints, and instructs us to delete that last constraint we applied, which is Constraint 62.
  • Instead, scroll down the Combo View window, past the Solver Messages and Edit Controls areas (widgets), to the Constraints widget. From the Constraints widget, select Constraint 43 and press the Delete key on your keyboard to delete it.
  • Sketcher Solver reports no redundant constraints in the Solver Messages area and also reports that there is 1 DOF remaining.
  • Now you can set the distance between the inside of the pulley cheeks by selecting one endpoint from each of the horizontal line segments, or instead by selecting the vertical line segment that connects the two horizontal ones, and applying the Vertical Distance Constraint.
  • Now the Sketch is Fully Constrained.
FC-Architecter wrote:
Thu May 10, 2018 6:21 pm
2) put a horizontal constraint on the line segment. <--- I just did this on my guinea-pig copy file and it works! The sketch is fully constrained. This is not one of the solutions you mentioned. I hope I will not run into trouble later with this.
The Sketch is good now because it is fully Constrained and the geometry is the way it should be.

Rod wrote:
Fri May 11, 2018 7:29 am
Would be nice if the arcs could give a 90 degree/45 degree preset indicator like lines have the horizontal or vertical helper.
I think that 90 degree arcs in the Polyline tool would be nice to have too, especially after starting with a vertical or horizontal line segment. I'd like to see it added to the mode cycle so that it happen at the 4th M key press, which would be after the tangent arc and before the first perpendicular arc.

Comments, anyone (before I write up a ticket)?
Edit: issue #3472

The way it is now, I usually have to add Vertical or Horizontal Constraints to a bunch of line segments between arcs after quitting out of the Polyline tool. I'm not sure a preset 45 degree arc would be as helpful.

edited to add link to ticket
Last edited by bejant on Sat May 12, 2018 9:39 pm, edited 2 times in total.
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FC-Architecter
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Re: How to use M function in polyline

Postby FC-Architecter » Fri May 11, 2018 5:01 pm

GeneFC wrote:
Thu May 10, 2018 6:37 pm
..... I believe that most helpers, however, have just about run out of gas regarding the current issues you are having with the tutorial.

Gene
photo.jpg
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GeneFC
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Re: How to use M function in polyline

Postby GeneFC » Fri May 11, 2018 8:56 pm

Better hurry. Prices are expected to rise rapidly.

:lol:

Gene
Rod
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Re: How to use M function in polyline

Postby Rod » Sat May 12, 2018 7:38 am

GeneFC wrote:
Fri May 11, 2018 8:56 pm
Better hurry. Prices are expected to rise rapidly.

:lol:

Gene
Due to OpeC (OPEnsource Contributors) cutbacks, help will be in reduced supply:
- Mon. Wed, Fri - left hemisphere brains only
- Tue, Thur, Sat - right hemisphere brains only
- limit of 5 questions per learner.
Sun - closed (contributors day of rest).

Would hate to see FC-Architecter give up on FreeCAD over an exercise or two (or see contributors move to some proprietary CAD forum where they might get paid for giving advice :ugeek: ).

Try a blank sketcher and just play with making longer M strings of lines and arcs until you are satisfied. Before stroking the M key pull your guiding line out a bit; then stroking the M key and watch the changes the guide line goes through until you get to what you want, then click to confirm; then repeat the routine.

When doing the exercise don't worry about sticking to the given dimensions - it is sometimes distracting or confusing to repeatedly stop and start a video then do your copying. You know the shape outline well now, so just make it regular to your own specifications.

I've gone through a few version of FreeCAD and it seems that what is working in one sometimes becomes corrupted or unstable in the next. My previous version of 17 would not let me make more than 3 bodies before crashing. I jumped to v18 to find it would not open the draft workbench. My current version of 17 (I consider reliable and doing what I want), and the version 18 I tried both often shut down for the first 2 or three starts then become stable; but the previous version of 17 almost always operated from start up (but would not make more than 3 bodies).

I'm one version of FreeCAD behind FC-Archetecter - very, very, very, very remote chance your version is giving some problems combined with new learner experience?

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13515 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: e17b340949b75a226cc7d89989b0aa238ccfc75f
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/Australia (en_AU)
Last edited by Rod on Sat May 12, 2018 11:34 am, edited 1 time in total.
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FC-Architecter
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Re: How to use M function in polyline

Postby FC-Architecter » Sat May 12, 2018 11:30 am

I am trying to change the radii of the fillets. Minute 8:13. of Tutorial 05a

https://www.youtube.com/watch?v=e6murcd ... 8q&index=4

When I click on the arc itself, it shows 12.70 mm in property view. But as you can see from the screenshot, the arc value is 3.175.

If I select that art and click radius in the constraints tools, it shows a radius of 3.17. If I try to change that to 6.35, this is rejected. The message is "Negative datum values are not valid with the constraint with index 62"

Any help unraveling this would be appreciated (Is this the result of not following bejants advice earlier? I can't see any connection.)
ARC_AND_PROPERTY_VIEW.png
ARC_AND_PROPERTY_VIEW.png (25.45 KiB) Viewed 199 times
RADIUS_FILLET_ARC.png
RADIUS_FILLET_ARC.png (13.69 KiB) Viewed 199 times
RADIUS_CHANGE_REJECTED.png
RADIUS_CHANGE_REJECTED.png (23.23 KiB) Viewed 199 times

I have just attempted to redo the sketch by following bejants advice:

"With Constraint 43 existing, apply a Horizontal Constraint to the upper horizontal line segment of the inside of the pulley cheek.
Sketcher Solver gives a message that there are now redundant constraints, and instructs us to delete that last constraint we applied, which is Constraint 62.
Instead, scroll down the Combo View window, past the Solver Messages and Edit Controls areas (widgets), to the Constraints widget. From the Constraints widget, select Constraint 43 and press the Delete key on your keyboard to delete it.
Sketcher Solver reports no redundant constraints in the Solver Messages area and also reports that there is 1 DOF remaining.
Now you can set the distance between the inside of the pulley cheeks by selecting one endpoint from each of the horizontal line segments, or instead by selecting the vertical line segment that connects the two horizontal ones, and applying the Vertical Distance Constraint.
Now the Sketch is Fully Constrained."

I removed constraint 43 then attempted both to

a) select the 2 point of the vertical line between the cheeks

AND b) just the line itself, then set a vertical distance constraint of 41.275. Freecad wont let me do it. I think there might already have been a constraint there, that I may have to remove.
05a_NEW3-2.fcstd
(19.07 KiB) Downloaded 11 times
schupin
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Re: How to use M function in polyline

Postby schupin » Sat May 12, 2018 12:35 pm

FC-Architecter wrote:
Sat May 12, 2018 11:30 am
When I click on the arc itself, it shows 12.70 mm in property view. But as you can see from the screenshot, the arc value is 3.175.
If you're in sketcher mode, the information highlited in the in the properties pannel are not connected.
If you want to change your radius, the easiest way is to double click on the arc within the sketcher mode and change the value.

I have no problem doing it with your file.

If you want to change the value from the property pannel, you can do it too, but you have ton find the constraint corresponding to your fillet (the third in your case. The one with a 3.17 mm value)