Drag fully constrained sketch

[johan.rutgeerts]

I have single component design, with only internal geometry (i.e. no references to external components, assy contexts, etc).

All sketches are fully constrained. Sketch 14 references some projected geometry:

Upon edit, I'm able to drag the sketch. It rotates around the indicated point. 

Notice that the projected lines also follow the drag.

The center point for the rotation is just the end of the projected line, afaik there's no particular reason why this point would be the center point.

The undo command indicates a sketch drag:

Is this some known behavior? Normally a fully constrained sketch cannot be dragged, can it?

Thank you,

Johan

[laughingcreek]

your correct that you shouldn't be able to drag a fully defined sketch.    could be a bug or operator error,  impossible to know with out more info.  from the screen shots it looks like your dragging a component. 

[davebYYPCU]

Rule No 1?  

Are those bodies being dragged too?  

Not enough top browser or other visible articles.  

Undo Delete - all bets off.

How did you get the black (circle / dot), from the elbow centre line, to move off the elbow?  

If only rotating.

2 possibles, all this is in an ungrounded, Component, or not a fully constrained sketch, with false indication of the contrary.

[whittakerdw]

I have had a similar problem before. I ended up having to dimension the part to the origin. The elbow may be dimensioned within itself, but if it isn't dimensioned to an origin, it is just floating in space. If it is already dimensioned to the origin, and the dimensions are in another sketch that just aren't shown in the screenshot, are you able to share you file as an .f3d file and attach it here?

[johan.rutgeerts]

As written, it is a single component design. So I cannot be dragging a component.

I singled out the example to just the three relevant sketches, see file in attachment.

Three things I notice:

1. Not all points can be used to drag the sketch, e.g. the one in green can but the one in red cannot:
   
2. There seems to be a sketch point in Sketch 1 that I cannot delete (indicated in yellow),
   
3. Project command cannot select the originally projected lines, which makes sense as they already have been projected. But the end points of those lines can still be selected for projection: 
   
   

   I assumed this might indicate that there's something wrong with the projection of, or the constraints on, those end points. However I checked and it's the same for a sketch that cannot be dragged.

Regards,

Johan

[TheCADWhisperer · Accepted solution]

First thing I notice is that Sketch 3 is not on the YZ plane?

I normally use the BORN Technique for most robust and predictable behavior.

This one is interesting...

If I do a Ctrl b (CMD b?) after moving - it returns to projected position.

I also notice an Offset in Sketch 3.

I often use Thin Feature or Shell or Thicken to avoid Offset sketch elements.

Edit:  If I remove the Offset constraint (and replace with Midpoint and Equal) the sketch doesn't move.

[TrippyLighting · Accepted solution]

@jeff_strater @Phil.E this is a bug, yet again related to the offset tool.

In my experience that tool creates so many problems that I almost completely avoid it. This has been going on for such a long time, perhaps it's time to completely re-write that particular function and not continue to attempt fixes.

There's just so much lipstick you can put on a pig!

[johan.rutgeerts]

@TrippyLighting is correct! It is due to the offset command and the bug is easily reproducible.

EDIT: as also is @TheCADWhisperer 

@jeff_strater @Phil.E see file in attachment:

• Draw some lines in sketch 1,
• Define sketch 2 and project one of the lines of sketch 1:
  
  
• Draw a shorter line onto that projection:
  
  
  
  
• Define an offset of the short line:
  
  
• The endpoint of the offset line can be dragged, and drags the full sketch with it:
  
  

I think it must be some buggy interaction of the offset geometry with the constraint solver: in this example if you add a dimension to the short line, then it's not possible anymore to drag (see image below). In the previously posted file however, the sketch was fully constrained and still could be dragged.

@TheCADWhisperer thanks for mentioning the CTRL+b command ('Compute All'), I did not know that shortcut!

Regards,

Johan

[davebYYPCU]

Wow, there are no words....

[johan.rutgeerts]

I consider it advisable to remove the offset command from the toolbar: