View Full Version : Flex Duct Dynamic Block or Add On

7th Feb 2013, 05:08 pm
Does anyone know of a dynamic block or any sort of add on for running HVAC flex duct in a drawing in AutoCAD LT 2D? I am trying to come up with any easy way to show more detailed duct work beyond just a single line.

Any help or suggestions would be greatly appreciated!


7th Feb 2013, 05:25 pm
I have worked a little bit in Google Sketchup and there is a command called "Follow Me", where you draw a single line and then place a circle at one end of the line. Once you select the Follow Me command you drag the circle along the line and end up with spiral duct for lack of better description. Is there any sort of command in AutoCAD similar to this?

Thanks very much!!

7th Feb 2013, 05:30 pm
Your best bet is to make a custom line type with a shape file (similar to the batting linetype commonly used to show insullation).

7th Feb 2013, 06:29 pm
I'm thinking you are not drawing a schematic so how flexible would this dynamic block duct have to be? Can you provide us with an image of some sort?

7th Feb 2013, 06:35 pm
It would have to be extremely flexible. I am thinking a dynamic block may be the wrong type of application. There may be something for purchase which I am hoping I might be able to purchase. Any ideas??

7th Feb 2013, 06:44 pm
None at the moment. I was pretty sure this wasn't going to be linear as far as flexibility went.

No image to share?

7th Feb 2013, 07:07 pm
Here is an image of what I am trying to recreate with the ability to manipulate it in virtually any way as far as extending turning and adding various fittings of different sizes when duct size changes.

7th Feb 2013, 07:16 pm
Well that certainly clears it up in my mind. I can't think of a way that you could get the flexibility you have demonstrated in your PDF. Maybe another forum member can suggest a solution. Good luck.

7th Feb 2013, 07:17 pm
The only thing I have come up with thus far is AutoCAD MEP. Nothing $5000 can't fix right! Ha!

7th Feb 2013, 07:22 pm
Does 2012LT have Path Array?

You might also look into the MEASURE command.

7th Feb 2013, 07:29 pm
Good suggestion! I am fiddling with it right now. Seems like it may be able to work pretty close to what I am looking for. A bit more work but no money out of pocket!!

9th Feb 2013, 06:20 am
Here is an image of what I am trying to recreate with the ability to manipulate it in virtually any way as far as extending turning and adding various fittings of different sizes when duct size changes.

you can try using this lisp

10th Feb 2013, 11:46 pm
The O.P. is using LT, so the LISP file will not work.

CCaldwell, the PDF you attached is definitely is definitely AutoCAD MEP can do, right out of the box. As SLW suggested, using a block and the MEASURE command to place the block along a center path to create the ribbed flex look is your best option if you want good two lined flexible duct display. Depending on the size of your projects, this could be a beating of a task.

24th Nov 2013, 02:09 am
I use the spline curve command to draw flexible ductwork and the diameter is set by the linetype scale when prompted. Note the macro will set your ltscale to 1 & psltscale to 0 automatically. This will only work with a drg ltscale of 1 so you need to work with object or layer ltscales within the drawing for all. It also creates a layer for you. I use the following Menue Macro in AutoCAD LT 2007 from a customised menu button.


^C^C_-ltype;load;flexduct;acadltiso.lin;;;^Cltscale;1;ps ltscale;0;-layer;make;m-duct-flex;c;white;;ltype;flexduct;;;ortho;off;-ltype;set;bylayer;;spline;\\^O;\\chprop;last;;ltsc ale;\;

For this macro to work you need to download the shape file BOX,es.shx and put in the correct autocad support directory depending on version.

You will also need to create the following custom linetype: -

*FLEXDUCT,Flexible duct [][][][][][][][][][][][][][]

You may need to play around a bit as may dislay differently in different versions but is a great macro.

Good luck and enjoy.