topic Re: Telescopic Boom Problem (Crane) in Dynamic Blocks Forum

Telescopic Boom Problem (Crane)

wojciech_sawczuk28PJH — Tue, 14 Oct 2025 07:46:04 GMT

Good morning! Ive recently started AutoCAD again, ive had a little past with it making small projects etc, but never used dynamic blocks. So its my first couple of days playing with dynamic blocks.

I want to make telescopic crane that extends and retracts jib, boom up and down, line up and down.

I can extend retract in given diameters (10k-20k mm)
I can boom up and down at given angles

Unfortunatley when i boom up and then try to extend or retract it only works in x and y not current angle
Line only stays when extending jib, but if i move mouse past 20k position boom stays but line moves
I have no idea how to make line go up and down

I can make line to stay looking down on simpler drawings but on this one it wont move at all when boom goes up/down. Attaching file and kindly asking for instruction. Thank you.

Re: Telescopic Boom Problem (Crane)

thefelttipfaerie — Tue, 14 Oct 2025 08:23:14 GMT

It looks like you also need to include the extend parameter in the selection set for the rotate parameter. Then the constraint will rotate to match the orientation of the geometry.

Tip: You might also want to turn off chained actions on the dimensional constraint.

Re: Telescopic Boom Problem (Crane)

j.palmeL29YX — Tue, 14 Oct 2025 10:59:25 GMT

@wojciech_sawczuk28PJH wrote:

I want to make telescopic crane that extends and retracts jib, boom up and down, line up and down.

Is this what you're looking for?

Or do you want explicitely one grip for the length and a second grip for the angle?

Re: Telescopic Boom Problem (Crane)

wojciech_sawczuk28PJH — Tue, 14 Oct 2025 11:34:58 GMT

Thats perfect, thank you. One more thing im struggling with its Line up and down (the little circle i just imaginary crane hook at the end of line)

Maybe its alot to ask for, but would you be so nice to record quick instruction with both? Im struggling with polar, tried to do it - but it doesnt retract or when i boom up or down its just showing radius where it supposed to be but the boom itself its not moving.

Re: Telescopic Boom Problem (Crane)

j.palmeL29YX — Thu, 16 Oct 2025 07:20:01 GMT

@wojciech_sawczuk28PJH wrote:

quick instruction?

Here you are.

(view in My Videos)

Re: Telescopic Boom Problem (Crane)

j.palmeL29YX — Thu, 16 Oct 2025 07:36:19 GMT

@wojciech_sawczuk28PJH wrote:

... would you be so nice to record quick instruction with both?

@wojciech_sawczuk28PJH

Were you able to follow the instructions given in the video above? If not, at wich point do you need further assistance?

Re: Telescopic Boom Problem (Crane)

wojciech_sawczuk28PJH — Thu, 16 Oct 2025 07:25:17 GMT

Thats perfect works very well. I really appreciate it