Would greatly appreciate if a good Samaritan is willing to look at my file and advise on how to figure out what constraints are needed.
It looks like all of the vertices are green when I click "find DOF", but lots of the edges are not green but I have not figured out why.
Any advice?
Seeking tips on identifying missing constraints in Sketch
Forum rules
and Helpful information
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help
Also, be nice to others! Read the FreeCAD code of conduct!
Also, be nice to others! Read the FreeCAD code of conduct!
-
- Posts: 12
- Joined: Fri Jan 21, 2022 4:19 pm
Re: Seeking tips on identifying missing constraints in Sketch
You have multiple instances of 0 mm dimensional constraints,, it is much better to geometric constraints and avoid 0 mm constraints.
This sketch has way too many constraints. You should use multiple sketches.
There is some symmetry that you could take advantage of a simplify/reduce the constraints making each sketch easier to read and maintain.
To find missing coincident constraints, use the Sketch Validate tool or just grab lines and attempt to move them.
This sketch has way too many constraints. You should use multiple sketches.
There is some symmetry that you could take advantage of a simplify/reduce the constraints making each sketch easier to read and maintain.
To find missing coincident constraints, use the Sketch Validate tool or just grab lines and attempt to move them.
- Attachments
-
- Screenshot from 2022-12-04 20-13-17.png (16.04 KiB) Viewed 736 times
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
-
- Posts: 12
- Joined: Fri Jan 21, 2022 4:19 pm
Re: Seeking tips on identifying missing constraints in Sketch
Thanks DrMacro!
I will have another go at it starting with a symmetry line and change the 0mm distances to vert or horizontally equal.
I will also do some more studying to see if I can do the same 2 objects in 2 separate sketches and then constrain them together afterwards - this was my preference anyway but I gave up and thought it would be easier if I did it all in the same sketch. I now see that it maybe isn't easier.
Thanks for the advice - I will persist!
I will have another go at it starting with a symmetry line and change the 0mm distances to vert or horizontally equal.
I will also do some more studying to see if I can do the same 2 objects in 2 separate sketches and then constrain them together afterwards - this was my preference anyway but I gave up and thought it would be easier if I did it all in the same sketch. I now see that it maybe isn't easier.
Thanks for the advice - I will persist!
- papyblaise
- Veteran
- Posts: 8001
- Joined: Thu Jun 13, 2019 4:28 pm
- Location: France
Re: Seeking tips on identifying missing constraints in Sketch
by dividing into 3, it goes much better, I used your sketch as master without trying to improve the rating
there are many unclosed points
there are many unclosed points
- Attachments
-
- Lego.FCStd
- (122.85 KiB) Downloaded 12 times
-
- Lego.JPG (25.25 KiB) Viewed 657 times
Re: Seeking tips on identifying missing constraints in Sketch
It sounds like you may be confusing "same position" with "connected". Two points with a relative distance of 0 mm are not automatically connected. That is why there are so many DOFs left.ManOfScience wrote: ↑Mon Dec 05, 2022 5:19 am I will have another go at it starting with a symmetry line and change the 0mm distances to vert or horizontally equal.
Rather than set a distance or an equal constraint you need to make sure that intended connections are really connected. Use "coincident", "tangent", etc.
Gene
- Shalmeneser
- Veteran
- Posts: 9560
- Joined: Wed Dec 23, 2020 12:04 am
- Location: Fr
Re: Seeking tips on identifying missing constraints in Sketch
- Attachments
-
- Lego Shelf Rings_SHALM.FCStd
- (90.67 KiB) Downloaded 13 times
-
- Capture du 2022-12-05 22-23-34.png (22.47 KiB) Viewed 513 times