Dynamic Blocks - Trying to create a pipe hanger with variable rod length

[Eric_M]

Hi. I hope I put this in the right category!

 

     I am trying to create a pipe hanger with a variable length rod hanger. But if I use the stretch action for a dynamic block it just moves the rod. I tried the scale command but don't see how to just have the length stretch and not have it affect the diameter. (file is attached)

 

Thanks!

Clevis_Models.dwg

[steven-g]

You can't stretch a 3D solid with the normal 'stretch' command Dynamic blocks only use ther standard 2D commands so if you can find something else that will work with stretch, but you will need to try different objects (maybe an extrusion - I really have no idea because I only use LT) otherwise you are out of luck, this is NOT what Dynamic blocks were designed to do.

Or look for a workaround eg. use overlapping solids and just stretch (move) one of them over the other to appear as a stretch.

[Eric_M]

Thank you. I appreciate the feedback.

 

  I am using Plant3D and know that their pipe hangers utilize a dynamic rod length. I am not sure how they do it.

 

  Thank you,

       eric 

[BIGAL]

If you drew the hanger from a number of objects say 3 blocks and a circle with a thickness you could change the length of the rod and say group the result or make them a new nested block. Draw say thickness 100, elev 0, circle 10 have a look at it in 3d.

[steven-g]

@Eric_M If you have a working example from Plant3D then post it here we should be able to see how that one works.

[Eric_M]

I have found out through an AutoCAD forum that Plant3D uses the Python programming language ( I don't know the first thing about it.)

 

I appreciate the feedback! 

thanks!

[lrm]

One approach may to consider the hanger as three parts, a block for the top (yellow), a block for the bottom (green) and a cylinder (red).

A simple vlisp program could place the two blocks and create the cylinder from 3 points (2 for the end ponts and one for the orientation) or some similar input.  How do you usually specify the location of a hanger?

[ReMark]

One would think that by now AutoCAD would have a 3D Stretch command that works similar to 2D Stretch. Take a look at this... a 3D Stretch command that works in AutoCAD.

 

https://www.simplecad.com/product/need-to-stretch-3d-objects-in-autocad

Edited December 30, 2021 by ReMark

[BIGAL]

If you entget a solid in this case a circle rad 5, 0,0,100 extruded 100 high, the only thing that made sense was these 2 assoc's 

(1 . "plane-surface $-1 -1 $-1 0 0 200 0 0 1 1 0 0 forward_v I I I I #") is it top

(1 . "plane-surface $-1 -1 $-1 0 0 100 0 0 1 1 0 0 forward_v I I I I #") is it bottom

(1 . "point $-1 -1 $-1 5 0 100 #") is this rad and height ?

 

This maybe the big hint "Open Design Alliance ACIS Builder" maybe there is a clue about codes. 

 

I think Lrm suggestion 3 blocks is simplest the rod can be stretched very simply as a 1 unit high block using scale.

 

PS Have a look at acisout and acisin. Its a text file made some changes and acsin and it doubled in height but no top and bottom may play again.

[steven-g]

Try this version, I just made a copy of the rod and used an 'array' on the copy which gives it the appearance of stretching. You may see a tiny gap every so often in the rod, I set the array distance to as close as possible to the length of the rod 4 71/128" (but that isn't the exact size) I'm more used to using metric sizes and being an LT user I don't have the commands available to edit the solid to a more user friendly length. Hopefully this will get you started though.

Clevis_Models(1).dwg

[BIGAL]

Looking on a another forum there may be a way of changing rod length and its pretty straight forward. Solidedit Face Extrude choose top circle/face of rod then Enter and enter a change value.

 

So if 100 now enter 100 will be 200, enter -25 will be 75 long.

 

Ok now the tricky bit pick the top of the rod ? Hmm (1 . "plane-surface $-1 -1 $-1 0 0 200 0 0 1 1 0 0 forward_v I I I I #") is it top

 

Added 4 to rod but its not a block anymore.

 

Edited January 2, 2022 by BIGAL

[SLW210]

On 12/28/2021 at 2:47 PM, Eric_M said:

Thank you. I appreciate the feedback.

 

  I am using Plant3D and know that their pipe hangers utilize a dynamic rod length. I am not sure how they do it.

 

  Thank you,

       eric 

 

Why not use the Plant 3D hangers?