Custom Feature: ProtoPipe – Totally tubular structures, totally fast.

roman_jurt190

Dear PiedPipers!

Link to the ProtoPipe

Every year, I challenge my Industrial Design students to an "intuitive engineering" contest: building bridges out of wooden sticks and 3D-printed nodes. Building these the standard way – juggling 3D-points, routing curves, queries, and pipe edges – works okay, but means a lot of going back and forth…

I wanted a tool that lets you drop 3D points on the fly, adjust their "Reach" to control connectivity, and instantly generate a prototype-ready structure.

Enter ProtoPipe! A fast way to design spaceframes that are easy to fabricate.

The tool is split into three simple tabs that guide you through the workflow:

• 3D-Points: Add and tweak your points, then set the "Reach." A Reach of 0 connects only to the nearest neighbor, while a 1 connects the point to everything in sight.
• Connections: Manually include or exclude specific lines if the automatic Reach settings need a little fine-tuning.
• Tubes and Nodes: Generate the final 3D geometry. And It preps the tubes so you can easily auto-layout them for fabrication later.

I'm not entirely sure if there is a massive real-world use case for this yet, so I’d love to hear what you all think. And maybe this is a case where a classic custom feature tree still makes more sense:)
But here are a few ideas to get you started

• Go big: Build structures way larger than your printer's build volume using standard PVC pipes.
• Scavenger prototyping: Use drinking straws, dry spaghetti, broomsticks, cardboard tubes, pool noodles selfiesticks….
• Print flexibility: We use SLS printers (which are perfect for the complex nodes), but standard FDM works perfectly fine too.
• Get flexible: inflatable bike tubes could create dynamic, flexible frames.
• Snap-fit Assembly: In an older Part Studio, I had partly open nodes working so you could snap the tubes in from the side – no sliding required!
  Bringing that back would mean changing the whole architecture, though...
  

MichaelPascoe

Ooo! 🤩

jnewth

I completely don't care how "massive real world use case" this is. This is super awesome. That's a good enough reason.

One extension that occurred to me: determine, from a catalog of joints, what the "closest" fit would be and build a nearest-fit version from that.

roman_jurt190

https://forum.onshape.com/discussion/comment/131606#Comment_131606

Thank you! You have to explain a bit more how you imagine this “catalogue of joins”…

As of now, selecting a point and setting the reach to 0 picks the closest point and makes just one connection. If there are 10 points, setting it to 0.5 will make 5 connections (from that point)… and 1 will make all connections.

Prior to this reach system, I played around with different ideas:

• generating a closed body from all the points and working with this
• defining the total number of connections that are allowed
• making more lines where the body walls are closer to each other
• I was trying to do topology optimisation without actually doing that :)

but i liked the simplicity of individual reach settings…

roman_jurt190

I did some real-life tests. I designed a laptop stand in 5 minutes, printed the nodes (in PA12 on your Fuse 1 printer). and cut and assembled the 2 mm stainless steel wires on the fly, using the digital model as a guide. This took me another 5 minutes.

I'm really happy with how quickly I could iterate through different ideas and node placements. The resulting structure is rigid while remaining lightweight and elegant.

I suggest unchecking "Generate 3D Nodes and Tubes" until you're satisfied with the construction, and only enabling it at the end.

MDesign

Wow… That's wild. nice job.

EvanReese

This is disgustingly cool! I recall chatting a bit about this kind of thing a while back and it's awesome to see the workflow so refined! I may have to buy a stock of little rods to keep next to my printer now.

EvanReese

Okay I replied before I even played with it. There's a magical (if unpredictable) amount of logic going on to automate connections with Reach which is interesting. It feels very fluid to use. It's great as-is, but in case you want some extra work here are some ideas 🙃:

1. include "add point on axis drag" option like Routing Curve. It makes creation even faster. If you drag an arrow it makes a new point, if you drag a square it doesn't. It's nice not having to mouse back to the UI over and over.
2. Handle nodes more like Routing Curve instead of how I did it on Freeform spline. It's better than managing a massive list of "node nth" which doesn't mean much.
3. Use point manipulators for mapping connections, rather than saying point 1 to point 4. Again, trying to push the interactivity. Maybe the multi-select capability recently added to Edit Curve and Routing Curve has something to teach?
4. Skip the auto-layout part and create an automatic Cutlist table instead. I don't think you're actually using Auto-layout for production, you are just trying to make an easy-to-reference collection of rods. Cutlist is the perfect solution here. It can have length and qty for each rod, as well as cross-highlight to the rods in the model when you mouse over the table. It can even be inserted into a drawing and ballooned if you wanted to just bring a 1-page drawing to the shop to make your cuts (though I'd personally just bring the iPad)
5. Add "description" to all of the parameters, so users get a tooltip on mouseover. Since you're using an LLM it should be fast.
6. Handle crossed beams with another joint (or at least make it optional). It's easy to produce beams that intersect one another, and for some build they might be fine to just bend past one another, but for other cases you'd want a joint there.

roman_jurt190

Thank you! And thank you @EvanReese for your ideas - very helpful ! Here are my comments:

1. Yes - this makes a lot of sense. At the moment it even spawns the new node at the second-to-last location... not ideal. I'm going to implement this.
2. Yeah - I think I'll just borrow the hole routing curve logic here.
3. Hmm - this is what I initially wanted, but it kept crashing. I never quite understood why it was possible to enter the positions but not select them. The agent was quite convinced that there was a logic loop preventing it. I'm not happy with manually typing in points either. And when adding a lot of includes/excludes, it also becomes quite hard to find them... hence the color add-on.
4. I was also thinking about a cut list, and sure, it's neat. But being able to navigate through the tubes in the graphics area while assembling and see the length written directly on the tube is quite nice. I think selecting a frame part will not highlight the corresponding cut-list entry. I'm trying to avoid creating a drawing altogether :) But maybe I could engrave the length and add the cut list as well...
5. Easy enough.
6. Yeah - crossed beams will become a problem with thicker tubes. Hmm. Automatically adding a joint could be cool, but it could also make things much more complex. With a hopefully better connection setup, selecting mirrored points and excluded lines should become easier as well. And I think it already does a good job of not mirroring points that lie on the mirror plane when mirroring is enabled.

What do you think could be nice add-ons in terms of reach? Maybe the number of connections as a parameter? For example, "3 connections within a reach of 0.5". Or perhaps a minimum and maximum reach, so it doesn't connect below or above a threshold?

What about additional node features? A cutout that allows tubes to be inserted from the side? Recesses for cable ties? Screw holes? Multipart clamshell nodes (although that's probably quite challenging)? Fully rounded nodes? (I tried that manually and it also seems difficult :) )

S1mon

I would recommend looking at Cutlist+. It will rename the frame parts based on frame profile and length. Cross highlighting works well too.
https://cad.onshape.com/documents/3ef342976bcbf59ab1fab2a0/v/8b262eacecdb724faac26890/e/7707d784b4c580d8122f592c

roman_jurt190

thanks simon! i will have a look!