Structural Member Annotation Scale Problem

[Hugh_Compton]

I've attached an ACA 2013 format file showing the following problem.

I have a Structural Member that I would like displayed as a single line with direction arrows.  The direction arrows scale fine when using low annotaion scales (i.e. 1:10 etc) but they disappear when the scale is larger (1:20 and above). 

Below the structural member I have inserted a normal acad line.  This line has arrowheads that schange size when the annotation scale changes, even for large scales.  This is the way that I want my structural member to work.

Does anyone know how to represent the structural member with a single line that has arrowheads that react to changes in annotation scale?

Thanks

[David_W_Koch]

I am not seeing any arrows at any scale.  There was a warning about a missing shape file (BVARROW.shx) - so I assume that your BVARROW linetype makes use of a shape from a custom shape file to generate the arrow graphics.  If you can post that SHX file, then maybe I will be able to see what you see.

One possible reason why your arrows do not display at scales smaller than a particular scale could be that since MSLTSCALE is set to 1 in your file, the effective linetype scale factor is multiplied by the drawing scale, and at smaller scales that number may be so large that it prevents the display of the arrows, as a complete dash pattern is not possible.  If you are seeing the arrows on the line in your drawing but not on the structural member, then that may not be the issue, since in a test with a different linetype that includes text graphics, it appears that the same scaling was applied to both AEC beams and AutoCAD lines.

[Hugh_Compton]

Hi David

Doh, forgot to post the SHX for the arrowheads as you mentioned! My post doesn't make any sense without it.  File attached. 

For anyone else looking at this the SHX file needs to be placed somewhere in AutoCAD's support path for the lines to work with arrows. 

[David_Knight]

I was able to replicate the problem, but I haven't a solution for you.

As a side note, just putting the SHX into the same directory as the file allowed it to open with the file.

[David_W_Koch · Accepted solution]

OK, now I can see the arrows.  I do not have time right now to deconstruct all of the things you did to get where you are right now and I have not worked a lot with custom blocks on structural members, but one thing I can suggest is that the problem may be one of scaling and the way linetypes work.

If you insert an instance of your custom block with the scale set to 1:10, you get one arrow in the middle of the block.  If you then change the scale to 1:20, that arrow also disappears, because the line length is too short to display the pattern.  (If you scale the block instance to a scale factor of 2, then the arrow returns, because now the line is big enough to show the pattern.)  Since you are  not applying the linetype to a line-based component of the structural member, but are instead adding multiple copies of this custom block as a custom display component, each block becomes incapable of showing the pattern when the scale is 1:20 or smaller.  I did not see a quick and easy way to have the block scale in size with the drawing scale.  Is there a reason why you could not use a line-based component and apply the linetype to it?  If the standard components do not work for you, perhaps you could add a custom block that is just a line, set to have one block scale to the length of the structural member, and then apply the line type to that custom component (on the Layer/Color/Linetype tab).

I will try to take another look at this later; I hope the above made sense and perhaps will lead you to an acceptable solution in the mean time.

[Hugh_Compton]

Yeah, problem solved!

As David stated it's nothing to do with the structural member at all - it's a simple line too short to display the pattern problem (I couldn't see the wood through the trees - kept looking at the structural member instead of the custom block).

To fix I simply made the custom block longer.  This updated the structural member automatically....

Not sure if there is going to be a CAD performance hit from having a longer block on the members? (Probably not since there should be less custom blocks on a structural member)

[David_W_Koch]

You can get a similar effect by assigning the linetype directly to a line-based component, such as the Beam Sketch component.  This can be done as a style override if you do not want the arrows on all beams.  I brought your linetype into a new drawing started with the Aec Model (Metric Stb).dwt template (United States content), where I used the Low Detail Display Configuration and, in a style-level override, assigned the BVARROW linetype to the Beam Sketch component (I also made the component color 80).  I drew a 5-meter long beam, and then viewed it at a range of scales on the layout tab.  Even with the linetype applying to the entire length of the beam, the arrow does not show at 1:200 scale, as the beam is too short to show the pattern.