Problem with sketches in experimental Assembly module

[nonlimited]

Hi!

I'm encountering problems when working with sketches.
When you deal with two parts and constraints, and a part is moved due a constraints, then you have problems in the visual part of the sketch editor:

The sketch will be visually positioned right according to the new part position, however, the GUI-interface(mouse input) is still located at the origin. You can see this by trying to select objects in a sketch, where the part has been transformed. Only if you are in the region of the origin, the selection will work.

I have uploaded a project file, where this situation seems to be conserved. Try to edit the "PlateSketch" inside Part "Part0".

[ickby]

Thats a known issue, but I have no idea until when this gets fixed. Currently best is to use step parts (or never edit your parts after assembling them )

[HurdyGuigui]

Hello,

I am currently working with the assembly module, and I am experiencing the same issue.
Any hint on how to solve this issue?
I could give it a try.

[logari81]

could someone post a screenshot showing the problem please.

[HurdyGuigui]

Here is a screenshot, you can see that my mouse pointer is on the left of the sketch to pre-select the line, because I changed the parent part position (+ 10 on x axis)

The easyest way to reproduce it :
-create a part in the main assembly, and change the part placement (lets say you put Base.x to 10)
-create a sketch in the body.
-try to create a line in the sketch, you will see that when you click to draw one point, the point won't appear at the mouse location, but translated on x +10

It is like the sketch itself respect the transformation of the part, but every mouse event in edit mode is still calculated from the origin, and not from the part Placement.

[jriegel]

thats quit clear. In assembly the position of each object is/can be result of an arbitrary tree above. More complicated it can even be a arbitrary directed graph (in case of multiple use and position of parts). Lot of tools in FreeCAD use still some kind of absolute positioning by reading the Placement of objects. In case of assembly thats simply wrong.

So we need some basic tools which can handle and retrieve absolute and relative potions of objects in FreeCAD. Unfortunately its in my head, but not document or implemented....

[logari81]

This is the problem that I assumed. Actually we had discussed about the positioning question like 2 years ago. Unfortunately we didn't come with a concrete common strategy about how to deal with the placement property. So that each of us had a different opinion/strategy in his mind. Myself, I used the invLoc trick in all part of the code that I worked with. Jürgen has probably something different in mind and jrheinländer something in between.

In my opinion an official Placement handling strategy should be the first thing to document before starting developping the assembly module. Jürgen if you have time to document/specify your strategy now, it is still a good idea to do. Any change in this strategy/policy will cause severe compatibility problems if it is done too late.