topic Re: Adjustable shower hose in Libraries & objects

Adjustable shower hose

Bruce — Thu, 06 Apr 2017 20:32:28 GMT

I need help in figuring out the best way to script a shower hose for a part I’m making (refer attached image). Normally, I would just use the TUBE command; but in this object, the positions for both the hand piece cradle, and the wall connection, are adjustable.

I thought the new NURBS suite of commands may help, but after researching a bit, trying to decipher the GDL Reference Guide, and actually trying a couple of commands, I’m not so sure (couldn't get them to work).

Any ideas would be appreciated.

Re: Adjustable shower hose

Barry Kelly — Fri, 07 Apr 2017 01:01:30 GMT

I would still use the TUBE command.
If you are using it now and can move one end then there is no reason why you couldn't make it move the other end as well.

The problem either way is that it will change the length of the hose so if it needs to be a set length you will need to adjust all the intermediate path nodes also.
If you are not fussy of the length then just adjust the end nodes (and of course the leading and trailing end co-ordinates.

Barry.

Re: Adjustable shower hose

Bruce — Fri, 07 Apr 2017 03:16:44 GMT

Thanks Barry. I was aware of those pointers, but that doesn't help with figuring out the drape of the hose. The wall connection can be higher or lower than the shower head. It can be close in or further way. It can be to the left or to the right.

What I'm really after is to get a TUBE to follow a NURBS path...but I don't think the new NURBS commands are up to that level of sophistication yet.

Do I mention that Revit could do this, or would that just be rude

Re: Adjustable shower hose

Anonymous — Fri, 07 Apr 2017 03:40:13 GMT

Would it be rude to mention that Cadimage have an object on the BIM Components portal that does this? Or are you trying to duplicate their one with a shower head of your choice?
(It does appear to be locked so maybe you don't have access to it)

Re: Adjustable shower hose

Barry Kelly — Fri, 07 Apr 2017 03:50:21 GMT

It could be done if you like a bit of maths and you don't mind a very uniform curve to your hose.
You would need the centre point and radius of the drape curve which would be based on the distance apart of the inlet and outlet.
Then use sin and cos to plot points along the curve for your TUBE.
Of course you know the start and end points.

I have done it using REVOLVE for the curve and PRISM for the vertical tubes (prism rather than cylinders because you can control visibility of the ends.
Again a very uniform curve.

The advantage of the TUBE is it would be all one element.
I have used a tube for a more natural shape on a bath spout with shower outlet but I did not make it adjustable.

Barry.

Re: Adjustable shower hose

Anonymous — Fri, 07 Apr 2017 04:03:12 GMT

Cadimage managed it with an irregular curve and stretchy too, so it's possible

Re: Adjustable shower hose

Bruce — Fri, 07 Apr 2017 04:08:54 GMT

@s2art: Not at all - that could be very helpful indeed (but I can't find it).

@Barry: Thanks for that. That gives me a direction for exploration. Cheers.

Re: Adjustable shower hose

Bruce — Mon, 10 Apr 2017 21:35:39 GMT

I managed to get it working to my (90%) satisfaction. The key is using quadratic equations to plot the TUBE points - i.e. it's a parabolic arc.

Next time I'll do some research into B Splines, as I think you can better control the smoothness of the curve at the low point. The parabola is a bit too pointy for a hose.

Re: Adjustable shower hose

Barry Kelly — Tue, 11 Apr 2017 01:50:16 GMT

I believe a 'cantenary' curve is more natural.

https://en.wikipedia.org/wiki/Catenary

Good luck.

Barry.

Re: Adjustable shower hose

Bruce — Tue, 11 Apr 2017 03:01:18 GMT

Excellent. I didn't know the name - that's good to know. Thanks again Barry.