Sketch is offset by small amount

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
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!
User avatar
Shalmeneser
Veteran
Posts: 9474
Joined: Wed Dec 23, 2020 12:04 am
Location: Fr

Re: Sketch is offset by small amount

Post by Shalmeneser »

Height must not be related to the radius.
Here 18 and 8 are not linked.
Attachments
Capture du 2022-01-19 19-40-49.png
Capture du 2022-01-19 19-40-49.png (8.77 KiB) Viewed 737 times
zoglub.FCStd
(9.31 KiB) Downloaded 11 times
drmacro
Veteran
Posts: 8865
Joined: Sun Mar 02, 2014 4:35 pm

Re: Sketch is offset by small amount

Post by drmacro »

Just for another take on how to do sketches...

Part object Image is not required.

Fewer constraints (thus faster for the solver), easier to read, easier to update...
Snip macro screenshot-699dbb.png
Snip macro screenshot-699dbb.png (142.65 KiB) Viewed 723 times
Snip macro screenshot-d9767f.png
Snip macro screenshot-d9767f.png (112.23 KiB) Viewed 723 times
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
dcschooley
Posts: 21
Joined: Sat Nov 21, 2020 10:20 pm

Re: Sketch is offset by small amount

Post by dcschooley »

Shalmeneser wrote: Wed Jan 19, 2022 6:42 pm Height must not be related to the radius.
Here 18 and 8 are not linked.
I'm not sure why that extra point is there. It's not supposed to be, and it's gone now.
Attachments
lower_clamp.FCStd
(47.71 KiB) Downloaded 11 times
servo_mount.FCStd
(186.67 KiB) Downloaded 13 times
dcschooley
Posts: 21
Joined: Sat Nov 21, 2020 10:20 pm

Re: Sketch is offset by small amount

Post by dcschooley »

drmacro wrote: Wed Jan 19, 2022 7:11 pm Just for another take on how to do sketches...

Part object Image is not required.

Fewer constraints (thus faster for the solver), easier to read, easier to update...

Snip macro screenshot-699dbb.png

Snip macro screenshot-d9767f.png
I put the Part object in because I thought I might need it in the future.

I'm not sure cutting the sketch in half and mirroring it works for me. I like seeing the whole thing in the sketch.
kisolre
Veteran
Posts: 4163
Joined: Wed Nov 21, 2018 1:13 pm

Re: Sketch is offset by small amount

Post by kisolre »

Shalmeneser wrote: Wed Jan 19, 2022 6:42 pm Height must not be related to the radius.
Here 18 and 8 are not linked.
Isn't that result of constraint preserving fillet? Point lies on both original edges.
drmacro
Veteran
Posts: 8865
Joined: Sun Mar 02, 2014 4:35 pm

Re: Sketch is offset by small amount

Post by drmacro »

dcschooley wrote: Wed Jan 19, 2022 7:31 pm
drmacro wrote: Wed Jan 19, 2022 7:11 pm Just for another take on how to do sketches...

Part object Image is not required.

Fewer constraints (thus faster for the solver), easier to read, easier to update...

Snip macro screenshot-699dbb.png

Snip macro screenshot-d9767f.png
I put the Part object in because I thought I might need it in the future.

I'm not sure cutting the sketch in half and mirroring it works for me. I like seeing the whole thing in the sketch.
Just a suggestions on efficient workflow (and how things work better in FreeCAD...). You are welcome to do it anyway you choose.

I've only been doing CAD for nearly 50 years, it's probably made me daft...I'm just an old crazy guy. :mrgreen:
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
User avatar
Shalmeneser
Veteran
Posts: 9474
Joined: Wed Dec 23, 2020 12:04 am
Location: Fr

Re: Sketch is offset by small amount

Post by Shalmeneser »

dcschooley wrote: Wed Jan 19, 2022 7:28 pm I'm not sure why that extra point is there. It's not supposed to be, and it's gone now.
This point is on the 2 lines. (It's the second fillet tool : keeping actual constraints.)
Attachments
NO
NO
Capture du 2022-01-19 21-06-28.png (1.18 KiB) Viewed 650 times
YES
YES
Capture du 2022-01-19 21-04-57.png (3.72 KiB) Viewed 651 times
dcschooley
Posts: 21
Joined: Sat Nov 21, 2020 10:20 pm

Re: Sketch is offset by small amount

Post by dcschooley »

drmacro wrote: Wed Jan 19, 2022 7:35 pm
dcschooley wrote: Wed Jan 19, 2022 7:31 pm
drmacro wrote: Wed Jan 19, 2022 7:11 pm Just for another take on how to do sketches...

Part object Image is not required.

Fewer constraints (thus faster for the solver), easier to read, easier to update...

Snip macro screenshot-699dbb.png

Snip macro screenshot-d9767f.png
I put the Part object in because I thought I might need it in the future.

I'm not sure cutting the sketch in half and mirroring it works for me. I like seeing the whole thing in the sketch.
Just a suggestions on efficient workflow (and how things work better in FreeCAD...). You are welcome to do it anyway you choose.

I've only been doing CAD for nearly 50 years, it's probably made me daft...I'm just an old crazy guy. :mrgreen:
I don't doubt that it is better, it's just a matter of getting my meager mind to work that way. How noticeable a difference does it make in terms of FreeCAD working better?
drmacro
Veteran
Posts: 8865
Joined: Sun Mar 02, 2014 4:35 pm

Re: Sketch is offset by small amount

Post by drmacro »

dcschooley wrote: Wed Jan 19, 2022 8:13 pm ...

I don't doubt that it is better, it's just a matter of getting my meager mind to work that way. How noticeable a difference does it make in terms of FreeCAD working better?
As for the Part object, unless you intend to create a quasi-assembly, it is just superfluous for a single solid.

As for sketches and constraints.

Sketches should always strive to be as simple as possible.

The solver work increases with each constraint you add, and not linearly. It also increases the likelihood unexpected behaviour by the solver. It solves the equation sequentially, and takes the first valid solution. That solution may not be what you desire, so the constraint scheme is important.

By using the symmetry of the part, it is easier, quicker and less prone error to make a change to the geometry, because you only need to change it in one place. So, something with an 8 hole bolt hole pattern can be changed in 8 places simultaneously if you have sketched just 1/8 of the shape.
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
User avatar
Shalmeneser
Veteran
Posts: 9474
Joined: Wed Dec 23, 2020 12:04 am
Location: Fr

Re: Sketch is offset by small amount

Post by Shalmeneser »

drmacro wrote: Wed Jan 19, 2022 8:25 pm Sketches should always strive to be as simple as possible.
so you can use Sketcher_External with less fear of TNP (check my file).
Post Reply