Mobile crane blocks

[robmcclymont85]

Hi there, hoping someone can help me out. Newbie here, only just learning how to create dynamic  blocks. When I add a rotate to a mobile crane boom I can't manage to keep my hook and cables at 90 degrees due to angle of boom changing. Hope this makes sense.

Thank you.

[j.palmeL29YX · Accepted solution]

HTH

If you need a more detailed answer post your .dwg file please. 

[robmcclymont85]

Thank you so much,  this is exactly what I'm after, Much appreciated.

[maviles06]

This was very helpful! Thank you

I have a question in line with Rob's request. i'm also working with cranes (tower cranes) and i started learning dynamic blocks recently. Is there a way i can rotate the jib but with it also stretch and rotate the pendant lines as i have noted below.

[j.palmeL29YX]

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th@maviles06 wrote:

Is there a way i can rotate the jib but with it also stretch and rotate the pendant lines 

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That should be possible. Post your block so I (or some other) can demonstrate a way ...

[j.palmeL29YX · Accepted solution]

Attached a simplified schematic solution. 

[maviles06]

Thank you so much!! that is exactly what i'm looking for. What were your steps, i have to reproduce this for various makes and models and jib lengths as well? i have tried in many ways to use the commands you have in the dynamic block but was unsuccessful in achieving this. i used your previous video on this thread to keep the line vertical as it's rotated, very helpful on maintaining the hook vertical!!

[j.palmeL29YX · Accepted solution]

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@maviles06 wrote:

What were your steps, 

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What shall happen with the both "lines" (marked with ???). They make no sense when the jib rotates (?). 

[maviles06]

That is awesome!! i see where my mistake selecting items when i added the point after polar stretch vs just selecting the polar parameter. The two lines will in question will rotate the same as the pendant lines. i will apply your polar steps to the safety lines as well!! much appreciated you saved me a lot of time when i have to rotate the jib on job layouts!!! my appreciation is understated in this comment.

[j.palmeL29YX]

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@maviles06 wrote:

The two lines will in question will rotate the same as the pendant lines. 

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For my fun only, how I'd do that. 

😉

[j.palmeL29YX]

In my suggestions above I found a (small ?) mistake.   😞

It is repaired in the attached improved version.  

[maviles06]

i will be sure to revise those two added actions into my block, i did notice that when i would rotate the jib. I have a new problem which arose as i was adding the tower sections into the block with array for incremental values on the sections. when i stretch the sections the rotate and stretching of the pendant lines gets nullified. Do you have any idea why this is?

[j.palmeL29YX]

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@maviles06 wrote:

 Do you have any idea why this is?

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You moved the complete crane geometry in y-direction, but the stretch frames remain on their initial (and now wrong) position.

You must repair all the stretch and polar stretch actions.  (one by one: Right click -> modify selection set - pick a correct stretch frame). 

[EDIT:]  Or see post #14 ...

[j.palmeL29YX]

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@j.palmeL29YX wrote:

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You must repair all the stretch and polar stretch actions.  

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Another way: 

To move the geometry upwards you must not use the MOVE command. Instead use the STRETCH command: Select all geometry including all actions completely inside a selection frame. Before you must have set BACTIONBARMODE to 0 (to be able to grab the actions). 

Good luck

[j.palmeL29YX]

In the meantime I added some small bug fixes: 

If you decide to use this version as base for the next modifications (adding the tower ...) I'd suggest, first to use the stretch command (in the block editor) to place the geometry to the needed new location (moved upwards) and then repeat the work to add the tower. 

Of course you also can ignore these small inaccuracies (they are only visible for large angles, but also for small angles they exist. I hate such botches 😉 ).