August 29, 2019

Revit: Yes/No Parameter Values

You might think that a Yes/No parameter can only have two values:
  • Yes
  • No
But, in fact, there can be three values:
  • Null
  • Yes
  • No
Null will only occur when a Yes/No parameter is first placed on an object, such as when you add an instance-based Yes/No Project Parameter to one or more categories in your project (for this example, Walls). After doing so, you will see something similar to this:
In the image above, the HasToggle Yes/No parameter has just been added to Walls. The toggle itself (the square in the value column) shows a check mark, but the check mark and the square are grayed out. You might think this means that the parameter is disabled, but if you look at the parameter name, it is not grayed out. Contrast this to the Enable Analytical Model parameter a few rows below the HasToggle parameter, where both the parameter name and the square are grayed out. The Enable Analytical Model parameter is disabled, because the Structural parameter (another Yes/No parameter) is not checked. The HasToggle parameter is enabled, but the toggle is grayed out to indicate that a value for the parameter has not yet been chosen, so the value is at its initial "Null" state.

Left clicking on the toggle will set the value to Yes, and the toggle is no longer grayed out.

Left clicking on the toggle again will change the value to No.

Once the toggle is clicked and an initial value set, you cannot set it back to Null, so, in operation, there are only two values, Yes and No, but you need to be aware that parameter can have that third value, Null, as that can have an impact on your model. For example, suppose the HasToggle parameter is used to drive two filters, that will be used to change the display of Walls in a view.
In the image above, you can see that two filters have been created, HasToggle-Yes and HasToggle-No, along with the properties of the HasToggle-Yes filter. The filter applies to Walls, and will select all Walls where the HasToggle parameter is set to Yes. The HasToggle-No filter properties are identical, except the filter collects Walls whose HasToggle parameter value is set to No. In the LEVEL 1 FLOOR PLAN View, these filters have been applied and an unattractive combination of colors has been assigned to the Cut Lines and Patterns, to make it obvious that the filter has been applied.

In the image below, you can see eight Walls in the LEVEL 1 FLOOR PLAN View. Two have had the HasToggle parameter set to Yes (checked), two have had the HasToggle set to No (unchecked) and the other four remain in the initial Null state. The Null Walls are not affected by either filter, because the value of the HasToggle parameter is neither Yes nor No.

August 27, 2019

AEC Answer Day - September 24, 2019

Another installment of Autodesk Answer Day, focused on AEC-related products, will take place in the the following forums:
  • English-language Users, 6:00 am (September 24) to 2:00 am (September 25) Pacific Standard Time
    • AutoCAD
    • Civil 3D
    • Revit
    • BIM 360
  • German-language Users, 9:00 am to 5:00 pm Central Europe Time (September 24)
    • AutoCAD Produktfamile - Deutsch
    • Revit - Deutsch
    • Inventor - Deutsch
    • Fusion 360 - Deutsch
    • EAGLE - Deutsch
    • PowerMill, PowerShape, PowerInspect & FeatureCAM - Deutsch
    • BIM 360 - Deutsch
    • 3DS Max - Deutsch
    • Maya - Deutsch forums.

More information, and links to the forums noted above, can be found in this Community Announcement. Stop in that day with your questions and interact with the Autodesk staff that will be taking part.

August 01, 2019

ACA: Got Blips?

Many younger users may have never seen "BLIPS" and many older users have probably forgotten about them. The BLIPMODE command and System Variable have been undefined in AutoCAD® and its verticals since the 2012 release. Back in the day, if BLIPMODE was turned on, every pick would be memorialized on screen with a small, white "+" mark. ZOOMing, PANning or using the REDRAW (yes, that command did have a function once) or REGEN commands would clear these temporary markers from the screen. But if you worked for a while without needing to change your view, you could accumulate a lot of these (and would probably quickly turn BLIPMODE off).

Undefined is not the same as removed, however, and the command is still there, and the System Variable can be accessed via AutoLISP. The System Variable was (is) stored in the Windows Registry, not in the drawing file, so someone could change the setting in the registry, as well. If you find yourself working in a drawing and having blips show up with each left mouse click, even if you remember "BLIPMODE," you will find that neither the command nor the System Variable is "known" by recent versions.

What to do? At the command line, type in the command with a period at the front: .BLIPMODE. The period tells AutoCAD to use the original definition of the command, and suddenly AutoCAD recoginzes it.

Press the ENTER key, and then choose OFF from the command line options.

Or, if there is someone in your office who is overdue for a (mostly) harmless prank, wait for her/him to leave her/his workstation with AutoCAD open. Start a new drawing, type .BLIPMODE, press ENTER and choose ON. Close the new drawing without saving. Discretely slip away, and await your colleague's return, and eventual annoyance. You may want to pop in and offer to fix the issue, before things escalate to an HR-level event. [Use at your own risk.]