See if you can stump the chumps with your SolidWorks questions at our session in SolidWorks World 2010:
Also, if you have files to submit as part of your question, please email your question and files to stumpthechumps@gmail.com.
Under ASME Y14.5-2009, Maximum Material Condition (MMC) can now apply to datums that are features of size and also surfaces. The 94 standard would only allow MMC on datums that were features of size and NOT surfaces.
The following is posted about datum changes with the permission of the author, David DeLong, who is a ASME GD&T Professional (GDTP) at Quality Management Services, Inc.
Under ASME Y14.5-2009, Maximum Material Condition (MMC) can now apply to datums that are features of size and also surfaces. The 94 standard would only allow MMC on datums that were features of size and NOT surfaces.
A feature of size is a hole or pin of any shape and also a width. In most cases in GD&T, the holes or pins are most important to assembly and are used a great deal as secondary and tertiary datums. Usually, the perimeter of a non-cylindrical part is not functionally important. There are certain cases where there may be a partial hole or cutout that is used in assembly and could now be referenced as a datum.
Maximum Material Boundary
The Maximum Material Boundary (MMB) is a new term used in the 2009 standard and replaces the terms “Maximum Material Condition” and also “Virtual Condition Size” when referring to a datums referenced with the maximum material condition symbol.
Let’s review the MMB for datum G in the above example. 
If datum G was referenced as a primary datum, the MMB would be the MMC size of the hole which would be the smallest allowable size of the 12 mm hole which is 11.6 mm. It does not make any difference whether or not the feature actually has a virtual condition size as shown, the MMB is still 11.6 mm..
In our example, datum G is referenced at MMC as a secondary datum so the MMB is 12 – 0.4 – 0.2 = 11.4 mm which is the virtual condition size of the hole. If the secondary datum did not have a virtual condition size, it would default to its maximum material condition size of 11.6.
Datum H Reviewed 
If datum H was referenced as a primary datum, the MMB would be its maximum material condition size or smallest allowable size – 8.6 mm.
The positional tolerance shown would give us a virtual condition diametrical tolerance zone size of 9 – 0.4 (MMC) – 0.3 (perpendicularity) = 8.3 mm.
So, if datum H was referenced as a secondary datum, one would use the perpendicularity refinement resulting in a MMB of 9 – 0.4 – 0.2 (perpendicularity) = 8.4 mm.
nce of a diametrical tolerance zone of 0.25 mm beyond the MMC referencing primary datum A (usually the mounting surface), secondary datum G at MMC (12 mm hole) and tertiary datum H also at MMC (9 mm hole).
We have already discussed that fact that the MMB changes depending upon whether it is a primary, secondary or tertiary datum. If there is any doubt about the MMB, one can reflect the actual MMB size in the feature control frame as shown above using brackets about the MMB size. This method can also be used if MMB size differs from the calculated size.
Let’s say we wanted the MMB size of datum H to be its refinement size of 8.4. One would then replace the 8.3 in the feature control frame with the refined size of 8.4 and that superseded the calculated MMB size.
For further details, please see the full article at Datums 2009.
The names for dimensioning methods within ASME Y14.5-2009 often do not match the common names. For example, what most of us call ordinate dimensioning is officially labelled as rectangular coordinate dimensioning. This can make finding information about certain dimensioning methods hard to find within the standard.
One dimensioning method that is particularly difficult to find is point location. A point location is where a point is located by the intersection of extension lines only. The method is known by so many other names.
SolidWorks uses the term virtual sharp. SolidWorks offers a list of options for the delineation of virtual sharp (i.e., point location), which is found at Tools pulldown>Options...>Document Properties tab>Dimensions heading>Virtual Sharps subheading. The only method supported by ASME Y14.5-2009 is the use of intersecting extension lines from two surfaces; so called witness in SolidWorks.
The standard does not require any other identifier or labelling. Yet many of us do feel compelled to add some sort of label to the dimension, using one of the above terms or their initials. A label does add clarity, particularly when the scale of a view makes display of a point location hard to read.
I covered this topic once before from a slightly different perspective in this article: Virtual Sharps. That article includes instructions on how to create a virtual sharp in SolidWorks drawings.
SolidWorks 2010 has made some minor tweaks to the control users have over balloons.
It’s been many years since ASME Y14.5M-1994 introduced the controlled radius symbol. Yet, we will still frequent find individuals in the industry who have never seen the symbol, nor know what it is. The symbol is CR.
It’s been many years since ASME Y14.5M-1994 introduced the controlled radius symbol. Yet, we will still frequent find individuals in the industry who have never seen the symbol, nor know what it is. The symbol is CR. Really, a controlled radius is actually just a radius that is a fair curve, with no reversals. I’ve not read ASME Y14.5-1982 in a very long time, but I believe this is actually similar to the original definition of a plain ol’ radius from the older standard.
Since ASME Y14.5M-1994, a simple radius has no fair or reversal limitation. As long as the arc of the radius feature’s profile falls within the tolerance zone, it is considered acceptable. These are represented by R.
So much time has gone by since the introduction of CR, I am left wondering why so many people have never seen it. The reason CR was created, as it seems, was to allow engineers to specify a radius without the need for it to be fair or non-reversed. This is good for breaking edges or filling corners. A CR would be more useful when fit and/or function is important, such as guiding features. In this way, the added expense of a creating a fair and non-reversed curve would only be employed when it is necessary for function.
This information was previously posted as part of another article, to which Vajrang Parvate (SolidWorks Corp Sr. Manager, Drawings Development) replied with an additional helpful hint. I’m reposting as a separate article to highlight the information.
SolidWorks has a new user-selectable behavior when a dimension is deleted. If the user deletes a dimension or even just removes text from a dimension, SolidWorks has the ability to automatically realign the spacing of the neighboring dimensions to get rid of gaps caused by that deletion. The user has the option to turn this ability on by going to Tools>Options…>Document Properties>Dimensions to select the Adjust spacing when dimensions are deleted or text is removed checkbox.
From Parvate:
…When the “Adjust spacing when dimensions” checkbox is checked and SolidWorks moves in dimensions after one is deleted, two commands are added to the undo stack : one for the deletion of the dimension and another for the movement of the rest of the dimensions. So hitting Ctrl-Z will undo the deletion in two steps.
