Obrounds - any progress?

[MikeHalloran]

I've been reading collected messages here and found quite a few workarounds, but I'm still annoyed that anyone has to do any working around... or maybe I just haven't found the right icon in SW 2009.0.0.

What's annoying me is that it's fairly simple to _model_ an obround of arbitrary size, using the obround generator in the sketcher, but dimensioning it in a drawing is another matter entirely.

SW will put in a center mark, but only if the obround hasn't been distorted (and internally decomposed, I guess) by running partially into a bend in a sheetmetal part. Okay, you can pick the midpoint of the straight lines and sketch in a center mark... but you shouldn't have to.

Now, how to dimension over the arcs? Any suggestions for that?



Mike Halloran
Pembroke Pines, FL, USA

 

[fcsuper]

Depending on your feature manager tree, you can add the axis to your slot before distorting it with other features...the axis should remain.



Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[CorBlimeyLimey]

"Now, how to dimension over the arcs? Any suggestions for that?"

Are you dimensioning the flattened or formed state views?

Was the obround placed between unfold and fold features?

Are you using the Insert > Model Items or manual method for dimension placement?

A screenshot would help.

 

[MikeHalloran]

Dimensioning in formed state.
No unfold/fold used.
I'm dimensioning the drawing.
I had some luck drawing in circles, putting centerlines across their quadrants, then erasing the circles and dimensioning the centerlines.

Luckily, it doesn't have to be a finished drawing.
I'm working from someone else's 2D AutoCAD drawings to generate 3D solid models from which I can export DXF files for the blanks. I've been generating and dimensioning the drawings as a way to check the model against the DWG files.

Yes, I could import the AutoCAD files and use the 2D to 3D tools to make models, and save some time... except that whoever generated the DWGs put some traps in them.

{
For one, the objects in the drawings are just inaccurate enough to produce parts that would fail inspection to the drawings. The errors are too systematic to attribute to sloppy drafting. Perhaps the drawings were filtered by a script of some kind to discourage exactly what I'm doing. Clever and sneaky. I admire stuff like that.
}



Mike Halloran
Pembroke Pines, FL, USA

 

[CorBlimeyLimey]

"I could import the AutoCAD files and use the 2D to 3D tools to make models, and save some time"
I very much doubt that you would save time. I've always found it quicker to redraw in SW ... because of the traps you mention, which seem to nearly always exist in ACAD drawings.

The errors might be caused by the SW importing process, but are often caused by sloppy drawing practices or by ACAD just failing to create correct connections.

 

[MadMango]

How are you creating the obround features?

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[MikeHalloran]

Extruded Cut on the Sheetmetal toobar,
then Centerpoint Straight Slot on sketch toolbar.

I noticed Design Library| features| Sheetmetal, but that doesn't seem to have a simple obround slot in it. Okay, it might; even the 'large' icons are too damn small.



Mike Halloran
Pembroke Pines, FL, USA

 

[CorBlimeyLimey]

Try Design Library > Features > Inch (or Metric) > Slots.

 

[MikeHalloran]

Tried Design Library > Features > Inch > Slots.

First impression: Works okay.

Second impression: Brain-damaged.

Okay, I didn't notice the push-pin, so I did three separate slots to get an array.

Tried linear pattern using a design library slot as an exemplar; that didn't work.

Tried entering "11.84+1.84" as the X coordinate of the third slot; the field is truncated, and wouldn't accept the last digit, so the slot location is wrong by .04".
Okay, it did make one of those aggravating 'clank' noises to warn me. If I were running with sound off (my company doesn't provide speakers) I wouldn't have noticed.

Now I have to break out the calculator.
Yes, I can do math in my head; it's wrong just often enough that I avoid it if at all possible.

Being able to enter an expression instead of number is a nice feature; why is it messed up by field size limiting and truncation in this corner of SW?



Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

One more set of slots:

I hit the pushpin.
It remembered the slot size, only.
Why did I have to reselect the plane?
Why did I have to reselect both reference edges?
Why did it use default coordinates again, instead of offering the coordinates I had?






Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

The Design Library slot didn't make dimensioning easier, either.



Mike Halloran
Pembroke Pines, FL, USA

 

[CorBlimeyLimey]

Can you post the part and drawing (or similar mock-up) to show what you are trying to do? Even a hand drawn sketch would help.

 

[MikeHalloran]

How about a screen shot?



Mike Halloran
Pembroke Pines, FL, USA

 

[CorBlimeyLimey]

Which obrounds are causing you grief?
I don't see any which are 'distorted' by a bend?

 

[MikeHalloran]

Oops. Wrong part. This one has good edge distances.

Sorry.



Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

Okay, here's one with distorted obrounds too close to a bend. I dimensioned centerlines drawn on circles.



Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

... The edge distance matter is sort of taken care of, i.e., I've found a workaround that looks halfway decent for obrounds that have been distorted or destroyed.

That leaves my original question/complaint: Given that SW maintains some internal knowledge that a small collection of lines and arcs _is_ an obround, why can't it give me pick points at the centroid and at the quadrants on the end, so I can dimension it quickly?



Mike Halloran
Pembroke Pines, FL, USA

 

[CorBlimeyLimey]

Hold the Shift key down when picking the obround arc and the dimension will snap to the quadrant points.

 

[MikeHalloran]

Thanks.



Mike Halloran
Pembroke Pines, FL, USA