This file documents the enhancements and problem fixes provided with dbMASS version 4.2. Please read to stay up to date on these developments.
----------------------------------------------- Version / Published
------------------------------------------------- 4.20 / April 5, 2001
------------------------------------------------- 4.21 / April 12, 2001
------------------------------------------------- 4.22 / April 14, 2001
1. New Features
|The Location Buttons used within the Entries Window now provide some very useful status information. Status indicators are displayed which allow you to make quick observations about the location status of the listed entries. The status indicators display whether a particular entry has a location offset or is cg located. Additional indicators are used to show whether a rotation has been applied and/or if a mirror of the entry is used. The status indicators used are shown in the adjacent image. The bottom two buttons shown without a labeled status give a couple examples of different combinations that can result.|
The Select Window used to request a class category selection during the class flow-up processing is now labeled Select Category.
A couple of situations were discovered which could cause some problems when an entry type was changed from a part to a project, installation or assembly or vice versa. If an entry with multiple configurations or effectivities had its type changed, not all existing configuration effectivity combinations for the entry were updated in the relationship table. This missed type change could result in some sub-entries not being properly displayed or included in reports. The second situation uncovered was that the mass item (overtyped) status of a part mass was not being cleared if the part was converted to a project, installation or assembly. The first situation has been overlooked since configurations were introduced in dbMASS, but the later was only introduced in version 4.0. Both situations are now being addressed properly.
When the Location Window mode was changed from cg mode to point mode the point on x and point on y were not being properly displayed. This was a display issue only and did not impact any results. None the less, the problem has been addressed so that now points are correctly displayed for this mode change.
A few problems with the MPEX export/import features have been identified and corrected. Brief descriptions of the conditions follow:
Item Points for CG Offset. When the cg of a part with shapes assigned is modified by editing the values within the Mass Properties Windows, dbMASS asks whether the items should be moved to reflect the change in cg. This feature has been working fine. The origin points (point 1) of the items were offset by the change in cg and the transformation reflected this change. However, the point 2 and point 3 values were not be adjusted. This oversight was not a problem unless the values were output in a report as is done with the MPEX export feature. The point 2 and 3 values are now correctly adjusted to account for the cg shift.
Negative Item Weight. dbMASS supports negative item weights. However, the calculated mass of an item will always be positive because negative material densities are not allowed. So if a negative calculated value is desired a negative sign can be applied to the calculated mass. The item mass is still considered to be calculated and dbMASS just manages the sign. When items with negative mass were being imported through the MPEX translator the negative sign was being drop in the recalculation of the items mass properties. This problem has been corrected.
Rotation Angles Preference. The MPEX format supports defining coordinate transformation in the same manager as dbMASS does. That is by specifying an offset point and either two additional points (point on x and point on y) or rotation angles. If both sets of data are provided the MPEX translator would use the point data to calculate the transformation. This has been changed so that now if the rotation angles are provided, they are used instead. The rotation angles tend to give a higher resolution specification then the points for the number of significant figures used.
A situation was introduced with dbMASS 4.0 and the linked uncertainty feature that could cause dbMASS to run out of memory during the database "Copy to" or "Copy from" commands. The situation is now more efficiently addressed so that this should no longer be an issue.
A scenario was discovered in which it was possible to introduce duplicate entry ids through the use of the Copy Window. The same entry id would occur multiple times with or without the same description or entry type. This was an undesired result that has been fixed.
Some code was introduced in version 4.13 that broke the MPEX standard part filtering feature. This version restores this capability.
When copying entries between databases one type of duplication detected and controlled is the occurrence of duplicated entry ids with a different description and/or entry type (project, installation, assembly or part). These duplicated descriptors (as they are called) are processed by the Duplicate Window manager prior to addressing duplicated entries. Selecting to "edit original" and "edit update" will display the Descriptor Windows as show below.
In some cases you may want to see which entries use (reference) a particular descriptor. Previously there was no method provided to view these entries during the duplicate resolution process. A new feature has been added to accommodate this situation. To access the entries that use the particular descriptor apply a right mouse click on the Descriptor Window. This will open a "Select Assigned to" Window. If there is only a single entry referencing the descriptor, i.e., no other configuration/effectivity combinations, the Entry Window will automatically open. For multiple references of the descriptor, you will need to select one of the configuration/effectivity combinations to view.
The dbMASS Word Macros make it easy to convert a dbMASS report into a Word document. The macros access information from the dbMASS directory to establish the active database directory location. A problem was introduced in version 4.0 that caused the Open Report dbMASS Word menu pick to give an invalid path error message. This problem has been corrected. This also fixed a problem which could cause dbMASS to not maintain the screen color between dbMASS sessions.
One of the features of the MPEX format support provided by dbMASS is the creation of displayable inertia shapes from what would otherwise just be mass properties data. In particular, dbMASS will create an inertia shape when a part in the ENTRIES data set has mass, inertia and a material assigned. With dbMASS version 4.0 the item quantity for these inertia shapes was no longer being set to 1. This would leave an item quantity of zero which would cause the part weight to go to zero even though the item added for the inertia shape had the correct mass properties. This problem has been corrected.
The Inertia Shape feature automatically creates an item with a shape that accurately models the mass properties of a part. It can be invoked either from the Part Window or through the use of the database import process. From the Part Window, first define the parts mass properties. Weight and inertia are required. Then select the items button. If there are no items already defined for the part, you will be asked whether you would like to create an inertia shape for the part. Selecting "yes" will then open the Materials Window so that you can define the material density to use. After selecting the desired material dbMASS will create an inertia shape if one is possible for the given material density. With the MPEX format, parts that are defined in the ENTRIES data set with weight, inertia and a material assignment will invoke the inertia shape feature. This little known, but powerful feature will allow you to create a graphical model from a spreadsheet of mass properties information. If you wish to learn more about this feature look up "inertia shape" in the dbMASS Manual index and/or consult with the MPEX documentation found in the MPEX folder within the dbMASS directory.
A few problems were identified and corrected with the inertia shape feature. The first and most significant problem was for parts with negative mass properties (mass and inertia). This case would produce several square root domain errors and then a divide by zero error when the feature was invoked. The second problem corrected was when a part has an inertia shape defined the mass item or overtyped field should have been cleared to indicate that the values are now calculated. This was not being done. The last condition corrected was to use "inertia shape" for the description of the item when created through the import process. All of these problems were introduced in either version 4.0 or an earlier release.
A bogus indexing error was being written to the indexerr.log file when more standard parts existed than entries and a standard part in excess of the entries was referenced in an assembly. This has been corrected.