ANSI standard for leaders
ANSI standard for leaders
(OP)
Is there an ANSI standard for leaders? Is it widely adhered to? I'm trying to establish standards for our office and this is one of the issues.
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ANSI standard for leaders
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RE: ANSI standard for leaders
John-Paul Belanger
Certified Sr. GD&T Professional
http://www.gdtseminars.com
RE: ANSI standard for leaders
Norm Crawford
GDTP-S
Applied Geometrics, Inc.
www.GDandT.com
RE: ANSI standard for leaders
Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
RE: ANSI standard for leaders
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: ANSI standard for leaders
I can understand the attempt to address the 3D environment. However, must of the "requirements" simply are not value added. For example, why is that we can not use an extension line for feature control frames or datum feature symbols? In 3D, using the common 2D extension line permits numerous advantages. One, more of the GD&T can be more organized and displayed in a single view.
Why is it that most if not all the annotation has to be in the same plane, a parallel plane, or perpendicular plane to the feature? Who cares? It is 3D.
Why does a leader line have to end in a DOT when associated to a surface? In 2D it makes sense, but in 3D; What is the value? These sort of details are only going to lead to a pile of human errors frustrating people who want to implement 3D annotation.
The standard has an exception for leaders to point to edges of "features of size" if it provides a clearer understanding. Why not surfaces? For example a profile of surface(s)? I know that the leader can also just point to the surface(s) with the DOT, but consider acceptance of 3D annotation. When within a "model view" that represents a 2D view, it makes sense to use a leader to an edge like we have done in 2D forever so that when the "model view" is shown or even printed, it looks like what the world is used to. Meanwhile, in 3D the queries clearly identify the features that belong to the annotation. Again, why do we need dots?
The query requirements are another major issue, but that is another thread, I am sure.
Some of what write here may seem petty. But to people putting the annotation on only to have to edit it or adjust a default etc etc to control dots over arrowheads, pointing to surfaces instead of edges (which I don't particularly like, but don't think it should be illegal), and the whole relative plane thing is going to slow 3D annotation down reducing it's major benefit, TIME.
I would love to get on the 14.41 committee. I've been doing 3D annotation for over 10 years and it just seems like the standard has choked some of the benefit with these details. IMHO
Norm Crawford
GDTP-S
Applied Geometrics, Inc.
www.GDandT.com
RE: ANSI standard for leaders
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: ANSI standard for leaders
Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion
&
RE: ANSI standard for leaders
IN THE BEGINNING, there were no standards governing the means of 3D drafting ... and manufacturing, design and military industries saw that this was bad. Each CAD company seemed to be taking their own path, with no commonality or consideration of industry as a whole; they either reflected their primary clients' wishes or went however they wanted ... and that was worse. Similar to the recognized need for a mathematical standard for ASME GD&T (Y14.5.1) to establish a common baseline, so it was with CAD capabilities. A couple of software suppliers participated in the original 14.41 development, but only one continues participation today. Some things make sense in the standard, and others do not necessarily, often because of the reader's own background & biases (for better & for worse). The issue of putting the leader on the surface vs on an edge seems trivial, but it was/is a substantial issue for CAD software and for graphical outputs. While most of us are of a background based on using 2-D drawing layouts where the edge is shown, a print made from a 3-D annotated model does not have to be shown in those classical views, and therefore a leader to any edge may be indicating either of the surfaces abutting it. Dot vs arrow ... trivial to me, but makes consistency in CAD much easier. Old software represented solids as wireframe geometries, with no attributes for what we visualized as the surface; if there's no attributes, then the leader couldn't be attached, hence all annotation was done to edges. To drive the software development, a requirement had to be put in place.
I was stuck helping to develop company drafting standards/practices and had to enforce them; what I found pretty much uniformly was that the detailers were pressed for time and didn't care enough about their product (i.e. the print) to worry about the rules. That doesn't mean the rules are at fault. Putting a dot on the end of a surface leader is no different from putting a capital letter on the first word of a sentence ... it's just a rule that you get used to and follow. In a legal contract that may be enough to change the meaning of an entire clause.
Personally, I find 3-D annotation in most packages to be ineffective and so difficult and time consuming as to be worthless. Comparing the package methodologies to the Y14.41 standards shows little in the way of adherence, but things are changing for the better as the new software engines and model databases are developed and implemented.
As far as I know, Norm, there's still seats at the table in Y14.41, and they don't make the support team sit at the kids' table either.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: ANSI standard for leaders
Y14.2 - 2.9.3
Y14.5 - 1.7.4
and for arrows:
y14.3 - 1.6.3.1
RE: ANSI standard for leaders
With regard to the leaders, I just want to summarize that there is room in a standard for "practices" and certainly meanings. That is to say; "know what a dot at the end of a leader means when used." I don't think it should be "required" to be used in 3D because of the overlapping requirements for "queries", which is yet another whole issue.
Most fundamental to me, in my personal opinion, is that the Y14.41 standard needs to be the future and what I am saying is that there should be no relevance to 2D drafting practices. In other words, lets stop making 3D look like 2D. That is exactly what reduces the time saving value of 3D annotation and "complicates" it's use and thus not as widely accepted as it really can be.
Lastly, although I having many thoughts for enhancement of the Y14.41-2003 standard and simply do not like some of what is in there, I have publically applauded the committee in the past and am doing so again for taking the first step in developing a standard that will live on. The pluses far outway the negatives!
Norm
Norm Crawford
GDTP-S
Applied Geometrics, Inc.
www.GDandT.com
RE: ANSI standard for leaders
RE: ANSI standard for leaders
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: ANSI standard for leaders
Norm, I'll send you the contact details.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com