Corrupt sketches

[csmith]

I chaps. I keep having the following problem, and the only resolution I've found is to scrap what I've been doing and start again

Put simply, I have a simple sketch (attached) that complains about conflicting constraints 12, 31, 33, 45, 47, 79 constraints that I don't have. The sketch is nicely green showing that I have zero degrees of freedom despite the notice. I can't delete the constraints, because they don't exist (or rather, they are not shown.... but wait....)

When I exit sketch, the constrained sketch disappears, and I get a few white lines that reflect the very early steps of the sketch I created. The same number of lines as conflicting constraints. I cannot select these lines as the vanish on entering the sketch.

If I hold "space" whilst in the sketch, the white lines do appear on-off-on-off-on-off on repeat, so I can get to see them, but they are unelectable .

I am running Debian jessie/sid, so my OS is pretty fresh, but it's been a few weeks since I did an aptitude upgrade.

Has anyone else seen this, or can reproduce the problem with my file?

Edit. I know exactly how to reproduce the problem now. Attached are two files showing the design progression up to the point it goes bad (three steps). First I draw the containing frame, second sketch in the shapes, third join up the nodes. Now, what I am doing is selecting the two nodes to join by dragging the select box around them. They turn green and I connect them. This generates the following errors:

Not able to delete a constraint on point with the given index: 7
Not able to delete a constraint on point with the given index: 5
Not able to delete a constraint on point with the given index: 3
Not able to delete a constraint on point with the given index: 1
Not able to delete a constraint on point with the given index: 0
Not able to delete a constraint on point with the given index: -1
Not able to delete a constraint on point with the given index: 35

If I click both nodes specifically with the mouse pointer (which is sometimes a lot of trouble, particularly with a trackpad!) and connect them, then everything is fine.

Container and rough sketch shapes

step2.png (17.31 KiB) Viewed 4247 times

Nodes connected using mouse select box

step3-sketch.png (17.23 KiB) Viewed 4247 times

Attached are the files that illustrates the problem.

OS: Debian GNU/Linux unstable (sid)
Platform: 32-bit
Version: 0.14.3637 (Git)
Branch: master
Hash: 0acb77e8def9434b2303aefacc3cfb097685ec0c
Python version: 2.7.7rc1
Qt version: 4.8.6
Coin version: 4.0.0a
SoQt version: 1.6.0a
OCC version: 6.7.0

[slc55]

I am a relative Freecad novice so I don't normally reply to requests for help but I'm just passing this way so I'll try.

When the sketch is in editing mode, change the constraints filter to ALL. The missing constraints will appear in the drop down list and can be deleted. The sketch then appears correctly when editing mode is closed.

OS: Ubuntu 14.04 LTS
Word size: 64-bit
Version: 0.14.3681 (Git)
Branch: master
Hash: ef08a61a4dbec598101e0c1aead95a031ef53f7b
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
SoQt version: 1.6.0a
OCC version: 6.7.0




Edit ....... Did you edit your post while I was replying? Something has changed!

[ulrich1a]

There seems to be a bug in the sketcher. If two nodes are selected with the selection box and one of the nodes is already connecting two lines, than at adding a coincidence constraint two coincidence constraints are added.

Whereas if both nodes are clicked, than only one coincidence constraint is added.

The sketcher has problems with multiple constraints constraining the same thing. This seems to be working the first time, but give problems at later stages in the sketching progress.
I consider the adding of multiple coincidence constraints when only selecting two nodes with the selection box a bug. The selection box seems to select three nodes and adds coincidence constraints for them. It should be checked by the sketcher, if some nodes already have a coincidence constraint, instead of adding superfluous ones.

Ulrich

[csmith]

Okay, cool. Well, as long as we know

It is a bit frustrating though not being able to mouse-drag select, just need to remember to click-select!

I'll try the filter idea, it only takes one mouse-drag select to stuff up the sketch at the moment, so hopefully that will be a saviour.

Do you want this logged as a bug?

[ulrich1a]

Do you want this logged as a bug?

It is always good to log problems, as they can than be solved some day.

Ulrich

[NormandC]

As I wrote in your other topic, this sketch is over-constrained. There are too many equality constraints. This certainly does not help.

[abdullah]

Hi guys,

There is a possible bug fix in my github:
https://github.com/abdullahtahiriyo/Fre ... master.git

In branch:
coincident_constraint_fix

Why this happens?
Because when choosing by clicking only the point "on top" of the two that are coincident is selected (only the one closest to the camera is picked by Coin3D), they the system is requested to make the third point coincident with that one (ergo one coincident constraint is added). When the selection box is used, the three points are selected, and two different coincident constraints are requested, point1 with point3 and point2 with point3.

What I did is:
Not to allow a constraint of the same type and same elements and positions to be added, if it is of type coincident.

Why only for coincidents?

Because otherwise it will ignore the user when for example trying to add an equal distance type constraint to a line when there is already one there, without showing any information about the conflicting constraint (other than the overconstraint warning).

If you think of more cases where this happens and the user can safely be ignored (like this one), just tell me and I add them.

If someone could test it a little bit before asking for a pull request... I really have to leave the computer now...

Regards,
Abdullah