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Disclaimer 1: I do not create that many drawings any longer. Most of of the work I do is Class A and organic surfacing projects.
However,I havehad an atypical amount of 2D work in the past month or so. While creating dims in WF5, I noticed that clicking the plus/minus button brings up the expected X.XX +.00 (superscript) and -.00 (subscript). All is right with the world.
However, the fun begins when I change the values for the plus and minus, especially the minus. If I do not explicitly type in the "-" (minus symbol),Pro adds a"+" inthe lower limit. So my dimension would look like: X.XX +.01 (superscript) +.01 (subscript).
To my knowledge there is never a case in ANSIwhere the plus/minus would/could both be a plus tolerance. This never is the case correct? Is this a programming oversight or is Pro allowing an allowable ANSI callout?
Believe it or not, I have had to do this in the past. I cannot remember the specifics right now but the callout required two "+" tolerances. Pro is actually designed to do that and it is, or was, documented in the manuals.
Kim
In Reply to Dean Long:
Disclaimer 1: I do not create that many drawings any longer. Most of of the work I do is Class A and organic surfacing projects.
However,I havehad an atypical amount of 2D work in the past month or so. While creating dims in WF5, I noticed that clicking the plus/minus button brings up the expected X.XX +.00 (superscript) and -.00 (subscript). All is right with the world.
However, the fun begins when I change the values for the plus and minus, especially the minus. If I do not explicitly type in the "-" (minus symbol),Pro adds a"+" inthe lower limit. So my dimension would look like: X.XX +.01 (superscript) +.01 (subscript).
To my knowledge there is never a case in ANSIwhere the plus/minus would/could both be a plus tolerance. This never is the case correct? Is this a programming oversight or is Pro allowing an allowable ANSI callout?
We are standardized on ANSI 14.5 for the documentation. If ISO is the only way it can be specified and we have ANSI specified, Pro is allowing something it should not. Right?
I did not recall any situations where, even under ISO requirements, I have seen any situation where two +'s were used in a dimensional callout. You are correct when stating is is"confusing". I can appreciate the "need" for the callout, as in a heat induced press fit. But I highly doubt any inspector will measure a slip fit "at temperature".Doesn't itstill seems less confusing to use +/- with one being zero and specify the tolerances based on process (I.E. heat) than use a +, + tolerance?
Does anyone have an example of it's use?
thanks
Thanks for the explanation Ben. I was not thinking in terms of your explanation nor the fact that some companies produce components that clients may process further and use +, + as a way of indicating there is always positive stock for them to lap, mill or otherwise fine tune.
I have learned a new thing today.
I think the issue is not the need for +/+ or -/- tolerances. Pro/E has always had the capability to do this and there are valid reasons why. What has changed is the default behavior when you enter a value for the minus tol. In the past, Pro/E assumed that this would be a negative value and if you input a positive value it displayed as a negative. To get it to display as positive you had to input a negative value. This was perhaps a bit illogical to the programner but entirely logical to the user who will want the lower value to be negatinge 99.9% of the time. Somehow, PTC has flipped this behavior, requiring the user to enter a negative value to get a negative display. This is going to cause a great deal of confusion and drawing errors. PCT should go back to the old behavior ASAP. I for one would never put into production use software that is behaving as the original poster says it it is doing now. (FWIW, I always stay several releases behind because of PTC's abismal record of fixing one bug and creating 2 new ones.)
So you had a solution that satisfied the 99.9% case and you blew it.
In Reply to Raphael Nascimento:
Hi everybody.
Just wanted to chime in on this thread...
I think this change was made a little bit before I took over the
drawings area, but I believe the reason was to support the use cases
already mentioned by others for when +/+ or -/- tolerances might be
needed. Although they are somewhat rare, we do need to provide some
support.
So, from a functionality point of view we need to provide the ability
for +/+ or -/- tolerances, but from a usability point of view forcing
the user to type in the minus sign to get the 90% case isn't, in fact,
all that usable. One of the things we're considering for the future is a
smarter way of doing things that satisfies the 90% case with minimal
effort, but still provides the option to achieve the 10% case. Hopefully
we can sort this out in an upcoming release.
Thanks,
Raphael
http://www.ptc.com
Raphael Nascimento
Product Manager
T 781.370.5916
E -
PTC.com http://www.ptc.com