[Ticket #4250] Sketcher placement and its axis visualisation

[Pauvres_honteux]

Hi, I'm missing the possibility to explicitly place my sketch on a plane of my choice and a point of my choice. And staying connected to the plane and point in such a way it follows them if/when I move them.
As it stands now I sometimes can make this happen, but it is still not editable after it is attached to the plane and point. Further I can not set or edit the orientation of the sketch.
In Part - Sketch things are really static, in PartDesign - Sketch is a tiiiny bit more cooperative.
I'd like to have this fixed like this:
.
1) There shall only be one sketch in FreeCAD started/created identically everywhere it is used.
2) When initialized I expect to be asked to add information about plane, center point and axis orientation.
3) When double clicking on an existing sketch I expect to be presented with a pop-up window where the plane, point and axis orientation is editable. It est, I can change the location of the sketch (plane/point) and orientation of the axis.
4) When inside the sketch I expect to see the sketch center point and its axis in the tree. These shall be selectable as references when sketching.
.
Catia sketcher example
.

Sketcher_4.png (19.02 KiB) Viewed 2489 times

.

Sketcher_5.png (187.85 KiB) Viewed 2489 times

.

Sketcher_6.png (41.28 KiB) Viewed 2489 times

.
I'm not alone it seams: Axis cross over Zero point

Edit reason: clarification.

[chrisb]

but it is still not editable after it is attached to the plane and point. Further I can not set or edit the orientation of the sketch.
In Part - Sketch things are really static, in PartDesign - Sketch is a tiiiny bit more cooperative.

In Part you can change the Placement of a sketch at any time after creation. This includes translations and rotations. In PartDesign you have to change the AttachmentOffset.

[Pauvres_honteux]

In Part you can change the Placement of a sketch at any time after creation. This includes translations and rotations. In PartDesign you have to change the AttachmentOffset.

.
I've made a couple of files to play with. The sketch shall go on the plane I created and the sketch shall be placed with one of the points I created at its center and the axis shall be oriented as the user wishes.
.

Sketch_placement_Body.FCStd

(8.16 KiB) Downloaded 40 times

.

Sketch_placement_Part.FCStd

(7.94 KiB) Downloaded 42 times

[saso]

This is again something that I was thinking about recently...

It was actually from this discussion https://forum.freecadweb.org/viewtopic. ... 0&start=90 ... To make the long talk short, my conclusion from it and so the suggestion would be to extend the current attachment options from current (on the left), to one as shown in the image below (on the right). And yes, for all objects that have the attachment property not just sketches. I invite everyone to try to understand the idea, IMO it should work and be very cool

[chrisb]

The sketch shall go on the plane I created and the sketch shall be placed with one of the points I created at its center and the axis shall be oriented as the user wishes.
.
Sketch_placement_Body.FCStd

Find attached the file for the PartDesign version. The Attachment is:

[Pauvres_honteux]

.
Thanks for that file. Now you've proved it is possible to attach a sketch to an arbitrary plane.
So the only thing left is make that macro/script be the default to pop up when one wants to create a plane! And the axis orientation thingie of course.
.
Anyone against me making a feature request in Mantis?
.
The developer would, naturally, want to know where to find this macro/script for implementation. Can you Chris, please, add that information?

[RatonLaveur]

at the risk of sounding terribly like a broken record, this really comes back a lot towards the following open topics:
-better control of datum plane orientation
-better visualization of datum plane object LCS

overall, the mechanism is already there to fully control your sketch attachment and positioning, it's the Local Coordinate System. it could use a little more love with regard to its integration to other datum geometries (points, lines, planes) and sketch options as you suggest.

my current workflow is create the correct LCS. create the datum plane of that LCS for further reference/usage with other sketches. then create my sketch.

i think whoever decides they have the time and interest to tackle your proposition should benefit from considering the whole picture.

[chrisb]

I didn't use any script, it's the common attachment dialog. You reach it via the properties of the sketch: Click on AttachmentOffset MapMode and then on the three-dots-button appearing at the right side.

[saso]

Find attached the file for the PartDesign version.

Yes, this has been discussed and shown that it can work also in the topic I linked above and this works for any sketch, regardless in what WB you work and it actually works for any object that has the attachment property... But this result to attach a sketch to a plane and also set its origin is actually a sort of a "side effect", the possibility to pick several option in the attachment dialog is actually meant for to be able to position an object also indirectly (ex between two planes). The above suggested improvement to the Attachment functionality, that is to split the attachment setup in to selection of the "support" (could be the plane in this examples), the "origin" (could be the points in this example) and the "orientation" (could be implicit in this example), it would be a more proper and more complete implementation that would give the user the real control over all this options. What the implicit option means is that the user does not explicitly set the origin or the orientation, but that they are by default automatically inherited from the parent (placement) object. So what this additional options would give us, is basically the ability to place an object on a plane between two planes and set its origin in the middle between two points and set the orientation of it relative to a direction between two lines... Something like this is not possible at the moment, would IMO be however very cool.

[Zolko]

Anyone against me making a feature request in Mantis?

yes, me. Sketch and datum objects work very well the way they are. They could get some love to improve aesthetics and usability, but it's very low priority and therefore not the good moment to add noise before v0.19 is released.

Please learn to better use the available tools and make a constructed proposal for v0.20. I, for example, would like to move the datum objects from the PartDesign namespace to the Part namespace, to avoid the irritating "Links go out of scope" warning when using datum objects directly in an App::Part.