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Offset curves bugs (#2147)
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jlm  
#1 Posted : Saturday, March 21, 2009 4:53:26 AM(UTC)
jlm

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Hi,

See on attached files :
I need to offset the blue profile out 0.05mm for EDM sparkling distance.

>>> If I select the curves one by one, I get the black profile, but the 2 small fillets cannot be offset.

>>> If I do it all with "select chain", I get the red profile. The 2 small fillets appear OK, but the top spline look snaky...

2 methods, 2 different bugs.

JL
File Attachment(s):
Bug offset splines.sfx (12kb) downloaded 5 time(s).
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Steve.M  
#2 Posted : Thursday, May 14, 2009 12:11:29 AM(UTC)
Steve.M

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These offset problems need to be addressed.

pic attached showing a joined curve with offset to each side, neither is correct.


Come on Tim, these basic functions should be working correctly. we are on version 6 of a CAD system that cannot offset, this is ridiculous.


- Steve
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Tim Olson  
#3 Posted : Thursday, May 14, 2009 9:28:07 AM(UTC)
Tim Olson

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Steve

If you can post the file with the offset value that would be great. ACIS will stop offsetting a curve if the offset value is invalid relative to the curvature.

Tim
Tim Olson
IMSI Design/Encore
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Steve.M  
#4 Posted : Thursday, May 14, 2009 11:47:10 AM(UTC)
Steve.M

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Tim,

I would of thought offset failures due to curvature would be consistent in that values above a failure would also fail, and that when loading the same file a failure made would again fail, but that does not appear to be the case.

I do not have the original file, but have made similar which gives similar results (attached).

I have attached a pic showing various offsets made which show various results.




- Steve
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dudko  
#5 Posted : Friday, May 15, 2009 3:25:43 AM(UTC)
dudko

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Yes, offset-command is very bugy.
Pity, really an important feature for contour milling.

Other bug example! (tested in VC5)
offset two or more objects simultaneously, resolution is automatically set at medium. ??????Why??????
dudko attached the following image(s):
offB.jpg (39kb) downloaded 5 time(s).

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ttrw  
#6 Posted : Friday, May 15, 2009 6:10:05 AM(UTC)
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Originally Posted by: dudko Go to Quoted Post

offset two or more objects simultaneously, resolution is automatically set at medium. ??????Why??????


My guess is that this isn't a bug, but an oversight that needs updating, going back to the days when CU ran on really slow PC's and had crappy graphic cards, so a lower resolution was picked instead, to help aid performance? Of course in this age of Intel Core Duo 2's things have moved on somewhat, and/ or I may just also be talking out of my a*se!! lol!

I'm sure Tim will fix this? :D
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Tim Olson  
#7 Posted : Friday, May 15, 2009 12:26:52 PM(UTC)
Tim Olson

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>>I would of thought offset failures due to curvature

Hi Steve,

This is not a bug, but is the intended action by ACIS. ACIS will offset the curve up to the point where the curve will have an issue due to curvature. My understanding is that they attempting to preserve continuity of the resulting offset spline. ACIS puts an emphasis in creating continuous curves and surfaces for manufacturability.

I compared the results with SolidEdge (based on ParaSolids), which behaves the same. The curve is stopped where a continuity issue occurs.

I also compared with AutoCAD. I liked what they did, they offset the curve into separate curves.

Regards,


Tim
Tim Olson
IMSI Design/Encore
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Steve.M  
#8 Posted : Friday, May 15, 2009 2:07:40 PM(UTC)
Steve.M

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Hi Tim,

Originally Posted by: Tim Olson Go to Quoted Post


This is not a bug, but is the intended action by ACIS. ACIS will offset the curve up to the point where the curve will have an issue due to curvature. My understanding is that they attempting to preserve continuity of the resulting offset spline. ACIS puts an emphasis in creating continuous curves and surfaces for manufacturability.
But as I put forward:
Steve.m wrote:
I would of thought offset failures due to curvature would be consistent in that values above a failure would also fail,


------------------------------
Originally Posted by: Tim Olson Go to Quoted Post

I compared the results with SolidEdge (based on ParaSolids), which behaves the same. The curve is stopped where a continuity issue occurs.
You are stating as fact that Solid_Edge will give exactly the same result as in the image in my post 4?

I have never seen Solid_edge produce results as with the image I posted (post4).


EDIT:

Attached:- offsets as in Solid_edge


- Regards,

- Steve
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Steve.M  
#9 Posted : Friday, May 15, 2009 3:07:47 PM(UTC)
Steve.M

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Originally Posted by: dudko Go to Quoted Post
Other bug example! (tested in VC5)
offset two or more objects simultaneously, resolution is automatically set at medium.


You can add the resolution.ini file and set the medium the same as the high. :D


- Steve
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dudko  
#10 Posted : Friday, May 15, 2009 3:26:48 PM(UTC)
dudko

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Hi Tim,

other example with application based on IntegrityWare
Picture 1 = Offset without trimmed intersection
Picture 2 = Offset with trimmed intersection
Picture 3 = Viacad

I'm see trouble in intersections

Best regards
Eddi
dudko attached the following image(s):
1_OffwoI.jpg (13kb) downloaded 5 time(s).
2_OffwI.jpg (33kb) downloaded 5 time(s).
3_VC6.jpg (12kb) downloaded 5 time(s).

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Tim Olson  
#11 Posted : Friday, May 15, 2009 7:13:16 PM(UTC)
Tim Olson

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>> offset two or more objects simultaneously,
>>resolution is automatically set at medium.

Repeated, found and fixed in 835.

Tim
Tim Olson
IMSI Design/Encore
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Steve.M  
#12 Posted : Saturday, May 16, 2009 8:35:37 AM(UTC)
Steve.M

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Originally Posted by: Tim Olson Go to Quoted Post
ACIS puts an emphasis in creating continuous curves and surfaces for manufacturability.


Tim,

I have been pondering over that statement (I have seen you put that forward before)

From what can be manufactured to what I see can be done with Pro/shark then Acis (IMHO) must have little idea on what can be manufactured. I have seen Pro/shark refuse to produce surfaces that can be built in many other applications, I have also seen Pro/shark produce surfaces that would be deemed unacceptable.

With respect, I cannot agree with your statement.

I am currently seeing far too many problems, and if you put forward these problems are down to Acis, then Acis is not a way to go for Manufacture.


- Steve
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la mouche  
#13 Posted : Tuesday, May 19, 2009 2:05:05 AM(UTC)
la mouche

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Hello Tim,


this explain my post? and my question?


http://forum.punchcad.com/showthread.php?t=1971

Thanks
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