HELP: Stretching and Shrinking problem

Hi guys, I have this problem and I hope you guys could help me solve. I would appreciate a lot

The problem is describe in this photo below. If I miss out any information, please let me know.

I'm not sure whether to create an Autolisp to define a special stretch command to do this. Or whether to create the rectangle and the red lines in a block so they behave more interactive to stretching)

This could be done with, and would be well suited to the use of a custom DYNAMIC BLOCK.

I would not have thought a dynamic block could be capable of this. Possibly someone will post 1 that proves me wrong. -David

I would not have thought a dynamic block could be capable of this. Possibly someone will post 1 that proves me wrong. -David

I could well be mistaken about that David, I thought that with parametric constraints and a stretch array action in the middle, it would be doable.

Certainly doable with lisp, but personally, being illisperate, and appreciably less than stellar at creating dynamic blocks, I can neither create such a lisp, nor prove you wrong. I wax hypothetical.

Which is not to say, with any certainty, on my part, that it could not be done either.

The other thread the OP posted today also struck me as a candidate for a dynamice block.

I will be curious to see if any of the usual dynamic block suspects might take the bait?

Be that as it may, I am sure the OP would be grateful if you would oblige him, as I am sure you are much more than capable.

I have been intrigued by dynamic blocks since first learning about them a few years back, but have never honed my dynamic chops.

Is there a minimum distance for the middle red lines and/or a certain amount of lines at any given distance of the rectangle?

@DadGad, I've probably made 100,000s of anonymous blocks, exactly 0 dynamic blocks

With :

• Centering nested inserts
  
• Adjusting nested insert spaces with a max distances
  
• Aligning end spaces
  

All with a stretch command, I thought would take a reactor at a minimum

It will interesting to see what the more knowledgeable here others have to say.

-David

Had to make some p&id's (which is not really my area) and had to make some conveyor belts and since i new nothing about dynamic block i did some experimenting and used a hatch to emulate the rollers...

just a thought u know... if you can garante your drawing scale this might be a quick (and dirty) fix

In EFD_03 I made some blocks with a popup list for the different types.

gr. Rlx

EFD_01.dwg

EFD_02.dwg

EFD_03.dwg

Do you know what drawing you want to get as a result, jasonle215? In other words, what's the purpose of dynamic arraying lines along the path while stretching if it isn't just for testing how AutoCAD handle this task for which you don't really have a good justification and may in some scenario using reactors (like David stated) even crash while performing this action...

Is there a minimum distance for the middle red lines and/or a certain amount of lines at any given distance of the rectangle?

Minimal distance is varying :

* length = 2500 (2500 - (2x500); edges = 1500 in between (max. dist) => 0 line 1 space 1500...

length = 2501 (2501 - (2x500); edges = 1501 in between => 1 line divides 1501 on 2 spaces each little > 750 (min. distance))

* length = 4000 (4000 - (2x500); edges = 3000 in between => 1 line divides 3000 on 2 spaces each 1500 (max. distance))

length = 4001 (4001 - (2x500); edges = 3001 in between => 2 lines divides 3001 on 3 spaces each little > 1000 (min. distance))

* length = 5500 (5500 - (2x500); edges = 4500 in between => 2 lines divides 4500 on 3 spaces each 1500 (max. distance))

length = 5501 (5501 - (2x500); edges = 4501 in between => 3 lines divides 4501 on 4 spaces each little > 1125 (min. distance))

...

and so on

...

* length = 16000 (16000 - (2x500); edges = 15000 in between => 9 lines divides 15000 on 10 spaces each 1500 (max. distance))

length = 16001 (16001 - (2x500); edges = 15001 in between => 10 lines divides 15001 on 11 spaces each little > 1363.6363 (min. distance))

...

* length = 151000 (151000 - (2x500); edges = 150000 in between => 99 lines divides 150000 on 100 spaces each 1500 (max. distance))

length = 151001 (151001 - (2x500); edges = 150001 in between => 100 lines divides 150001 on 101 spaces each little > 1485.1485 (min. distance))

...

if length -> ~ => max. distance = min. distance = 1500 and number of lines -> ~

I see it now, all the instructions are a bit hard to read.

test_by_chau.dwg

Needs a bit of cleaning up but you should be able to get there from here.

David have a look at this. Not sure but civ3d has a whole lot of car parking blocks that are dynamic just stretch and they make correct pattern this includes a kerb at each end so this could be first and last roller.

Parking Tools - Imperial.dwg

Parking Tools - Metric.dwg

Thanks everyone. I think iconeo and Bigal's posts have given me some ideas. I'll let you know how I go with this

[ATTACH]55078[/ATTACH]

 

Needs a bit of cleaning up but you should be able to get there from here.

Hi Iconeo,

Thank you for making this for me. I was wondering if you could describe how create this block and with what constraint elements? I'm just trying to make this on my own but I'm not familiar with block. Thank you.

I checked out Iconeos dynamic block earlier, and tried to tweak it a bit, as it will exceed the 1500 measurement by a small amount before adding another element into the array, but I failed to get it sorted. BIGAL's post is a bit of a different animal, because the stretch action parameter is Incremental, instead of infinite, but still gives you a pretty good idea about the whole concept of dynamicism in blocks.

I checked out Iconeos dynamic block earlier, and tried to tweak it a bit, as it will exceed the 1500 measurement by a small amount before adding another element into the array, but I failed to get it sorted. BIGAL's post is a bit of a different animal, because the stretch action parameter is Incremental, instead of infinite, but still gives you a pretty good idea about the whole concept of dynamicism in blocks.

yeah, I think Iconeo's dynamic block is exactly what I need but I can't seem to replicate this on my own. Can you give me a tutorial how the stretching works for the red lines? I assume it has something to do with array but I can't seem to do it. I would appreciate a lot if you could show me. Thanks heaps!!!!

Hi jasonale215, I've modified Iconeo's dynamic block to suit my analysis... HTH, M.R. (You have to click on both arrows for stretching)...

test_by_chau.dwg

Hi jasonale215, I've modified Iconeo's dynamic block to suit my analysis... HTH, M.R. (You have to click on both arrows for stretching)...

 

[ATTACH]55088[/ATTACH]

Thanks Marko_ribar,

I think Iconeo's dynamic block is the answer for my problem. However I don't know how he/she could use the expression for the Array Items as "arraycount+1" . I tried typing that in but CAD recognize my expression. Do you have any idea?. Thanks

While editing block, click on array path object ( small vertical lines - black ) and type ctrl+1 - property... Then in cell for number of item - just below (method - Divide), type d4/1500+2 as an expression... This is how I managed to set up array by path... Of course, you have to set up firstly d4 dimension and other constraints parameters... HTH, M.R.

While editing block, click on array path object ( small vertical lines - black ) and type ctrl+1 - property... Then in cell for number of item - just below (method - Divide), type d4/1500+2 as an expression... This is how I managed to set up array by path... Of course, you have to set up firstly d4 dimension and other constraints parameters... HTH, M.R.

Thanks for your input Marko, you have reinvigorated me to go back and try again, as it was entering that expression which was giving me trouble.