More about ribbed hoses

[N. W. Perry]

(Prior discussions here and here.)

1. I believe part 72706 should have 10 ribs rather than 9, as every photo I can find of the real part does.

2. Dimensions: I took some screen measurements from photos like this one, which support a rib-to-rib pitch of 2.5mm or 6.25 LDU, matching current practice. That also supports an overall length of 25mm, which is closer to the nominal 3L size of the part (especially with the natural squishiness of a real hose). It also also supports the 2L/6-rib hose being less than 16mm, as discussed in the second thread above.

3. I think the rib subpart should be a little fatter and rounder. In particular, the width of the rib should be greater than that of the gap; my measurements give an approximate ratio of 7:3. I plan to re-work this subpart for my own use; is it worth doing so officially? This would also affect the flexible segments k01 and k02.

[Thom Kok]

I would like it to be official if that is possible. Having the part as accurate as possible would make it more appealing for bricklink studio to add this part as well. I asked about it to the StudioPart github repo owner, because I want part 78c13 (71944) to be added. He also mentioned the length issue to me. Link to his response: https://forums.ldraw.org/thread-26143-po...l#pid45681

[N. W. Perry]

I would like it to be official if that is possible. Having the part as accurate as possible would make it more appealing for bricklink studio to add this part as well. I asked about it to the StudioPart github repo owner, because I want part 78c13 (71944) to be added. He also mentioned the length issue to me. Link to his response: https://forums.ldraw.org/thread-26143-po...l#pid45681

What is it about the length that they don't like? Will they not accept it if it's not modeled to be exactly 13 studs long? As per the discussion so far, whatever the naming convention, these parts really don't come by stud length but by number of ribs (and/or the length in mm, as a multiple of the rib pitch of 2.5mm).

Note that my reworked version doesn't change the length, because the current rib pitch is correct. It just looks more like the real hose, in my opinion. (I use it to generate LDCad flexible hoses, but the donors could be assembled into static versions as well.)

[Thom Kok]

I think it has probably to do with the bricklink naming of the part. If the length is correct for every hose, I could mention it to Vincent. He would probably want to add it then. If your change will be official, then I could mention it on the bricklink studio forum as well.

[N. W. Perry]

I think it has probably to do with the bricklink naming of the part. If the length is correct for every hose, I could mention it to Vincent. He would probably want to add it then. If your change will be official, then I could mention it on the bricklink studio forum as well.

I suggested two changes, but I'm afraid I still don't understand which one you mean, or how it solves anything for Bricklink?

First, I believe 78c03 should have 10 ribs instead of 9, but this part is already in Studio so that does not seem to be an obstacle for them.

Second, I think the actual ribs should look a little fatter and rounder, and the gap should be narrower than the ribs themselves. Here's a picture showing both of these differences (my part is on the bottom):
   
Note that my 10-rib hose is closer to the 3-stud length, but it's not exact. Only multiples of 5-stud lengths will come out evenly.

But, this says nothing about the 13L part, and in any case we don't control the Bricklink naming. If they need it to be called "Hose, Ribbed 7mm D. 12.8125L / 10.25cm" in order for it to be allowed into Studio, then that's really their call.

[Thom Kok]

I suggested two changes, but I'm afraid I still don't understand which one you mean, or how it solves anything for Bricklink?

First, I believe 78c03 should have 10 ribs instead of 9, but this part is already in Studio so that does not seem to be an obstacle for them.

Second, I think the actual ribs should look a little fatter and rounder, and the gap should be narrower than the ribs themselves. Here's a picture showing both of these differences (my part is on the bottom):

Note that my 10-rib hose is closer to the 3-stud length, but it's not exact. Only multiples of 5-stud lengths will come out evenly.

But, this says nothing about the 13L part, and in any case we don't control the Bricklink naming. If they need it to be called "Hose, Ribbed 7mm D. 12.8125L / 10.25cm" in order for it to be allowed into Studio, then that's really their call.

oops. I meant to say that if the length of each hose is already correct right now as you say, then I should send a message to Vincent to tell him it is alright to add them to the github repo. The naming is fine. Me and Vincent thought that the length was incorrect. This was probably the reason why the hoses mentioned by Vincent were not added to studio yet. Your desired change looks good. It would be great if this gets used instead of the current version.

[N. W. Perry]

oops. I meant to say that if the length of each hose is already correct right now as you say, then I should send a message to Vincent to tell him it is alright to add them to the github repo. The naming is fine. Me and Vincent thought that the length was incorrect. This was probably the reason why the hoses mentioned by Vincent were not added to studio yet. Your desired change looks good. It would be great if this gets used instead of the current version.

Got it. Well, the 13L hose on LDraw has 41 ribs and is 255 ldu in length, which equals 12.75 studs long and 102mm. That's a hair shy of the 102.5mm I think it should be, and 2mm short of what TLG considers it to be (104mm, which would equal 13 studs, 260 ldu or 41.6 ribs). However, photos of this part in real life show a range of 38-41 ribs, and of course it also depends on whether the particular specimen you measure has been cut exactly at the midpoint between ribs.

So, in short, there are a number of different lengths this part could correctly be, and the LDraw part 71645 is one of them.