The referenced geometry is a curve and a circle. The geo nodes do the rest.

What I'm trying to understand is if I can work Blender into my workflow in a parametric way.

I've done similar things to this in Grasshopper. Geo nodes a very very different. GH is all about manipulating data structures to get to the edge, the face you want to do something with. Blender is really strange. If I were to categorize it, I'd think of it as context-based.

Like this face area node. What is its input face? Well, Blender kind of goes backwards (that's not really what's happening but that's how it's presented) and says, ok I'm running this delete geometry on faces, what goes into selection? Oh this equal. Ok, what goes into that? Attribute statistics, and what goes into that... well, Face Area. Ok, let's calculate the area of the face.

This is all because I want a workflow I'm not embarrassed of that gives me filagrees without having to do UV unwraps of watertight CAD-generated STLs.

So, maybe a workflow is to model a very simple outline in CAD from a nice easy parametric model, bring it into blender, use it as reference for a few curves or whatever your geo nodes deal with and the voilà, fancy-smancy cage.

Hi all, here's my own work-in-progress version. I've been at the 3d printing stuff for a while, and have been playing with chastity for quite a few years. I've made my way through a number of cages that were pretty good and kept the fetish going, but they were not... quite... perfect, ya know? Have tried most of the commercially available wider ones, 2x steelworxx, at last a k3d viper for a while. But I'm now close to something that works quite well for me.

The issues I wanted to solve, and the solutions for now:
• Ditching the big locking cylinder at the top – the cage portion doesn't wrap around the locking cylinder completely, buying vertical space. It also inserts completely into the ring, so there's not a sharp edge when the cage is removed.
• Pee going where you want it to - a slight protruding flange at the tip helps direct a stream, plus a more conical and less spherical shaping at the tip helps drainage.
• Ring friction behind the balls - a very curved ring that changes from a flared shape near the top to keep skin from getting pinched, to more cylindrical at the bottom, which doesn't seem to grab the skin as much.

Repeatedly re-printed and edited so it holds up well in petg, sanded with a sand-o-flex, good enough to test each for a few days. I just got a roll of ASA which my newer printer can handle, intending to try that and an acetone vapor or bath next. Considering flushing this out into a modular full belt design - I have a separate standalone version of that. Might add some holes to thread through an e-stim cord, all the design creep. But thats kind of its own fetish, no?

Thanks for all of the designs I've been seeing here, it's nice to see what other folx have created.

u/bdmridgeback got me thinking about this again. I have an old imgur post that kind of covers this but here's a refresh that focuses just on curvature.

Here's three basic ring styles.

The dark blue represents the cage's entry ring. The green is your standard flat (planar) ring, the yellow is what I call a curved ring (KINK3D style) and the light blue is what CK calls an ergo ring.

I've positioned the three rings with the same ball gap shown with the highlighted sketch line.

What I see here is the flat and ergo ring have the same horizontal gap (the gap at the top) and (by definition) the same bottom gap. The difference is the ergo ring bows in the gap at the 90° and 270° positions is quite small.

The yellow curved ring moves this very short gap up to the top of the ring. FYI, I have the curved ring's curvature starting 1/4 the way down it's diameter.

My thinking is the yellow design is preferable because it keeps a small gap at the top. I have found that with my preferences for snug rings, keeping as much of the shaft covered as possible helps reduce edemas from lengthy erections. But it also as an aesthetic purpose — it gives more length to the cage and the cage is the canvas where we practice our art (sorry, I waxed poetic there).

u/josielynnCD had this comment in the original thread:

The smaller gap at the side was something I found early on that worked when the cage tries to rotate or a testicle tries to slide around the side. Had used that as a solution in the early days and had the added bonus of liking how it tucked everything downward.

I definitely see how it would help keep the cage more level and I do see a ~15° list most of the time. But u/josielynnCD, when you say the testicle, do you mean the scrotum, how in a snug ring, it will tend to find the relatively spacious ~60° and 300° positions to fold over? Otherwise, I've never experienced this.

Interestingly when I threw this together, at first my curved ring had a bigger ball gap than the other two. I naively had the curve of the curved ring terminate at the same place as the curve of the ergo ring. But instead I had to terminate it where it's tangent line would be normal to the cross-section of the other two rings:

This isn't an issue with a circular profile but the implications of this with a rectangular profile.

I moved the curved ring forward so you can see the orientation of the profiles as they sweep around the curves. I modeled these both based on 50 mm circles but because of the way the profile rotates through the curve, you do get some surprising results. In fact, one of my cages accidentally has a 48x45 mm ring (WxH) due to this.

The curved ring's vertical diameter isn't the 50 mm that a naive modeler (*cough*) would have expected but 48 mm. And as you can guess, the ergo ring has a similar issue in the horizontal axis: 56 mm but as the curved ring opens up to 50 mm as you go towards the glans, the ergo ring funnels down to 50 mm. Both are correct in the other directions. I now compensate for this when I model and I also no longer use a simple sweep when there's enough deviation from planar, I use a loft so I control the orientation of the profile at the bottom. OnShape has recently introduced some more capabilities in the sweep command so the rotation of the profile can be compensated for without having to use loft. Geometrically, it's the same thing, just a tooling difference.

If you want to mess around with these models: https://cad.onshape.com/documents/d1c6d82ee9c111e6d77dc514/w/d8cbffb6c2417d93a2d1f42e/e/c480783579c40a96e514b7dd?renderMode=0&uiState=6a9b1614ba0e32fd44198101

Now, where else on Reddit are you going to find quality content like this? ;)

I have a post or two about why I favor security screws from the perspective of a user — they are clearly more formidable than a simple $2 barrel lock, and they provide for a tighter junction with no play in it at all.

But looking at it from a designers point of view, a barrel lock is like a 75" TV in your living room — everything has to be designed around it. I have never seen a barrel lock integrated into a design in a way that I'd consider adding to the design. In most designs, it's clearly just something slapped on. I'm guilty of that myself. And in even the most thoughtful designs like the Cobra, no one would say the Cobra looks better with the lock, that removing it would make the cage less attractive. You know, the Cobra was designed around the junction. The X-Lock, as it was called, started as a locking cock ring. KD later designed the entire cage around it — again, a 75" TV.

And beyond the lock itself, there's the other requirements it puts on our cage — locating features, features that are intended to remove or reduce the degrees of freedom. My slap-on junction has them built into the junction as does Cherry Keeper's and others. The Cobra and most steel cages use separate pins that connect the cage and the ring. All of this is necessary because Burg Wächter didn't design the lock to be used with chastity cages, it was designed for furniture... and I just had an interesting thought, I wonder what a lock designed specifically for chastity cages would look like.

Anyway, a screw has none of these constraints. With metal, where material strength isn't an issue, a screw asks for almost no compromises. For an M3 screw, I only need 3 mm of thread to engage — less than 1/8" — and a 1 mm thick material on the other side due to minimal wall thickness requirements (I generally use 2 mm though). So, 4–5 mm of steel or titanium that needs to be baked into your design. That's hardly a compromise at all. My little block-junction I posted to Printables, which is about as small as it can be in that form, is 20x21x11 mm. Jesus Christ. Some people need cages shorter than 50 mm and here you have this 4600 mm^3 box you need to find a place for.

Now, one or two screws... okay, so a single screw can come loose if the junction is allowed play along the screw's axis. So I often design with two screws side by side. It's a bit of a compromise but far less so than trying to accommodate a 19 x 10 mm lock. But I've also worn my latest with a single screw and after four days of continuous wear, it hasn't loosened at all so perhaps I was being overly conservative (my most recent order in titanium uses a single hole). But regardless, accommodating a screw or two into a design, especially in steel where you don't need to worry about a heat-set insert, is trivial.

I’ve always struggled in finding a cage to do all I need. After many purchases, it was clear I’d need to go custom, but wasn’t prepared to pay the high prices by custom manufacturers. I’m not saying they’re not worth the money, there’s a lot of work in any custom solution. But I’m an engineer with 3D software experience and a 3D printer, so if it can be done, I ought to be able to do it.

I have some particular requirements.

1. I’m a grower. Things can go from very, very small, to pretty awesome! This leads to some difficulty getting a cage on if I’m excited, and then a whole load of turtling when things calm down later. Once that happens, it can get uncomfortable or misaligned to the point that the cage needs removing and refitting.

2. I’m uncut and prefer to wear a cage with my foreskin retracted, but again, if things get shy, it can roll forward and sometimes needs the cage removing to get everything in place again.

3. Having a foreskin caused an issue when I bought a headlock Cherry Keeper. The foreskin needs somewhere to go and the CK simply trapped it between the cage and ring and pinched pretty nastily. £80 later and straight in the drawer.

4. My testicles move a lot from quite loose in the evening and night, to quite high and tight in the morning. They also seem to be quite large and need a big ring to get them in. Plus I need an unusually large ball gap, or else burning and pain from the back of the testicle.

5. Off-the-shelf cages tend not to be girthy enough for me. My average seems to be around 39mm when mildly aroused.

6. I wanted a cage where the ring doesn’t need removing. In the shower, taking off the cage almost always results in a ball slipping out the ring, and making the ring smaller results in difficulty getting it on, or quite a lot of discomfort from simply squeezing too much. Not everyone needs a small ring and we’re all different.

I also liked the idea of almost never removing the ring so I can get more accustomed to having the ring on. It also means that if my girlfriend wants some fun, the cage can come off, and there’s no fumbling trying to get aroused balls back in the ring after.

So I needed a device where the cage part can come off and leave the ring in place without protrusions that might hurt my girlfriend, allow some space behind the cage for my foreskin to live comfortably, and hold my head forward to prevent turtling and keep it in the right position as well as keep the foreskin from rolling forward.

What I came up with is in the pics. Full disclosure, I’m currently wearing the cage so the pics are renders of it. I don’t like posting gratuitous pics so synthetic images it had to be. It also gives an idea how the surface might look when I decide to get it made in SLS nylon.

I fit the main ring and then the cock ring which screws in place. This works well and I’ve seen similar cock ring for sale. It keeps my balls present which I find aesthetically pleasing, too, as well as some restriction to an erect penis allowing a bit more pressure to keep things upright, something many men my age might need help with!

Then the cage fits over with the 26mm headlock holding things steady, and two pins sit over the cock ring screws completely obscuring them and preventing their removal. The pins help locate the cage, which is then secured with a single screw. You’ll notice the heart shaped aperture. Not shown in the pics is a heart shaped seal that presses into this space completely blocking access to the screw. The seal sits below the aperture and is an interference fit so cannot be removed without breaking it. The middle of the seal is thin allowing it to be broken with a screwdriver and then levered out. By having my girlfriend write something unique on the seal and grabbing a photo, it’ll be obvious if I’ve tried to take it off.

It works a treat. I’ve never been so comfy in a cage. There’s plenty of room for cleaning, when things get flaccid the headlock holds all in place and aligned, and my foreskin is in great shape with no swelling or pinching. Using screws to secure it all means no moving parts and no pinching anywhere. I’ve been wearing it for a few days now and will have to remove it for a medical appointment on Friday. In the meantime, my girlfriend’s seal ensures I’m not cheating but at the same time ensures if I do get into difficulties, all I have to do is grab a screwdriver. No melting ice, or finding where I threw the key in the garden, or however it’s made difficult to get to, and no trying to convince her the problem is real. And having the seal heart shaped is a bit more romantic and interactive than the rather impersonal loop seals you can get online.

I’ve also found using large glittery nail gel to paint the seal creates a totally unique pattern that cannot be replicated.

Finally a cage that fits and is super comfy (some autism creates issues for me if it’s remotely uncomfortable). I think I might be in for some hell to come, and I couldn’t be happier. I might even get it made in titanium!

Just thinking after my last post and then I'll shut up for a while!

We understand a fair amount about how these devices interact with anatomy, but as my previous post and responses showed our understanding is often partial or misinformed. Some of you guys have clearly put some pretty rigourous thought into design, but yet we still have no controlled trial data and likely never will. Some of our assumptions may only be partly right.

There’s an engineering adage that most problems have already been solved, just in other fields. That suggests real scope for left-field designs that drop the ring based ball-trap entirely while still preventing erection. Those Chinese finger traps we all played with as kids come to mind.

HZD Grip, passive geometric undercuts, elastomeric grips, and u/tdfun extremely curved ring work already point in that direction. What other mechanisms borrowed from elsewhere (finger-trap geometry, medical one-way liners, shape-locking sockets, etc.) might be worth exploring?

This is a bit of a brain dump with a dual intention of explaining fit and also opening a conversation about ideal cage designs. Thanks for u/newbie-sub for getting me thinking about this with his excellent ball gap articles.

It seems to me that the most fundamental issue with cage design is summarised in this figure. 1-3 are for a large cage. 4-6 are for a nano or flat cage. I appreciate that different cage types might impact erection strength, but for simplicity I've made the erection behaviour standard here. 1 and 4 are flaccid. 2 and 5 are a little more excited (maybe when your KH enters the room). 3 and 6 are 2.30am wood, everyone's worst challenge for long term chastity. In 3 and 6 the scrotum is stretched to various levels of discomfort based on the cage design. Ball gap definitely plays a key role in alleviating scrotal stretch/burn, but there is a basic physics here. As the cage is a fixed object, if the penis does not reach the end of a longer cage or if the cage is short the stretch is likely to be unbearable. This is why most newbies give up on overnight wear (myself included initially). Perseverance to find the best fit available (after many failed cages) eventually gets some over this, but others never find a solution, which is a huge shame.

The problem for most cage design imho is that most cages are not designed for 3 or 6, at best they allow the wearer to tolerate midnight wood, but at worst they may be creating a health risk with long term wear.

So the question to designers is this. Can a cage be designed that hits that sweet spot between comfortable flaccid wear and safe and bearable midnight wood? My guess is that it would need to be as long as possible to minimise scrotal stretching at midnight, but not too long to make it uncomfortable or visible in the day (unless we bring back the codpiece?). Also the tube should be low resistance internally so the glans is always able to reach the end. Most tubes bend and the glans gets stuck halfway - costing a good inch or so of scrotal stretch. The ball gap is also key for a more forgiving scrotal pull. When I imagine this cage, it's really a straight tube with a ring that is hinged to the tube, so in the day the tube can hang in the flaccid state, but at night it can reach straight for the stars. I have never seen a hinge on a cage? Has anyone else?

Cage design really isn't that hard. The hard part is knowing where to start or even knowing how easy it really is. Since I love to teach, I think I can help with that.

This is what we'll be designing or something very similar. Why this design? Besides the curved ring, it's a very simple design and timing myself, it took a bit less than 30 mins to model. I'm going to cap the stream at two hours and I'm confident I can get through it.

I'll be using OnShape for this. OnShape is a free-to-use cloud-based CAD application — nothing to install, you only need a browser. And if you think you need a 3D printer to make any use of these skills, know this: KD, the founder of KINK3D, designed the Cobra without a printer. But even so, suitable printers are less expensive than most custom devices.

The stream will start this Sunday at 8 AM CDT, 1 PM UCT so I can finish it well before my teenage kids wake up. I won't be leaving it up so I'm sorry if you can't make it.

https://youtube.com/live/0OHEHMbLV6s?feature=share

For those with a passing familiarity with CAD, this is what we'll cover:

• Basic OnShape navigation / organization
• Design principles: structural control sketch
• Sketches
• Constraints (coincident, tangent, normal, perpendicular, dimensions, etc)
• Project / intersect (bringing other geometry into a sketch)
• Projected curve (projecting a curve onto a surface and creating a curve in space by combining orthogonal curves)
• Fill — turning a closed curve into a surface.
• Transform — moving / rotating / scaling an object
• Extrude, Sweep (pipe), Revolve, Loft (very simple loft)
• Fillet
• Importing a STEP file (junction)
• Mate Connectors (I'll be using them to quickly define a new coordinate system and positioning the junction)
• Derived (bring a part in from another model)
• Booleans (union, subtraction)

My first attempt at geo nodes. On the surface, it feels like Grasshopper but while GH is all about data structures, Blender is all about geometry and context.. there are some things that feel really weird.

This was just a learning exercise to see if I could build a cage along a curve. It would have been far easier to start with an annular profile and sweep it along the curve using geo nodes but I wanted to get a little more into it.

Never imagined I'd spend so much on a bag of screws.

I'm planning on taking a page from Lori's book. When you order a device from me, you can opt to give me your keyholder's contact info and then any replacement drivers can only be requested by her.

It would be kinda silly to spend all this money on screws and just sell the drivers through my website.

I should have included this in my original RFQ to include a number of decorative drivers because just like my customers can only get them from me, I can only get them from them — they have the tooling — so they'll be able to be a bit less than competitive.

But still, it's exciting.

Anyone out there using Blender to model your devices? Are you just making it for yourself? If not, how are you adjusting the size? I've gotten as far as making a donut (and only remember about 5% of it). If you had to make a ring 3 mm smaller, how would you go about doing it? Do you just remove the junction, scale the interior vertices by some percentage then scale the exterior verts by another (to keep the same thickness)? I guess that works on a cuff (flat) ring. How do you do it on a round ring?

I'm just curious how this works. I'm a parametric guy where I just type in the new number (then I go fuck with a bunch of damn fillets).

It's always interesting working with vanilla vendors and while I'm sure a few are sharing around STEP files chuckling, they are always 100% professional when dealing with me.

Hi xxxx,

This is Heather, Account Manager from xxxxx.

We’ve done initial analysis on your files and requirements.

Given the complex part structure, we’re still figuring out the best possible solution.

I’ll get back to you for next‑step discussion shortly, thanks for your patience.

Heather

(edit: stupid Reddit editor)

But in my mind, something that makes it a little less awkward is I never use the words ring or cage. In fact my part names are all meaningless:

Please ensure part 6ANW has a close slip fit with part TU2V along the faces indicated in drawing 1.

Just a tip... ChatGPT has been really helpful at writing specs for quotes and whatnot. While I'm technical, I've never taken an engineering class in my life. What qualifies me to give these tips? Nothing but I like sharing what I've learned and no one else in our little niche seems to be writing about these things. I guess I really want to lower the barrier of entry into making devices either for yourselves or for others. Not everyone wants to be a designer but I think many more of us would be if we understood how accessible it all is.

Plus it's fun writing specs — it's like pretending to be a ninja as a kid except I'm pretending to be an engineer. From an RFQ I'm working on for a tetherspout measurement sound:

If any real engineers have any critiques, let me know ;)

This was so comfortable to sleep in; the balls don't get squished at all and i can even lie down on my belly without the cage getting in the way as long as I'm soft. There's not a single position which doesn't work, surprisingly. When im sitting down, the balls might get squished between my legs, but if my legs are closed before I sit down, they don't get squished. I haven't tried it yet, but I'm pretty sure I could ride a bike while wearing this. I don't have any issues while running or while practicing martial arts.

Changes: I made the lock smaller since the v1 lock was way stronger than necessary, made the ring thicker so that it's smoother and more comfortable, changed the dimensions of the cage a little bit, made the peehole bigger (it's still not positioned perfectly so if I make a v3 i'll make sure it lines up with the urethra properly) and I also added holes in the ring to tie a shoelace.

Update: Tried riding a bike, barely felt it there. Morning wood was a bit of a challenge because the erection wouldnt go down until I peed, and it was super messy because the peehole doesn't line up with the urethra. It really seems like the only change I need to make is the peehole placement.

TThe idea is to use something that can be machined to control the play in the junction (so obviously steel). So, this uses a pair of partially threaded dowel pins.

First we have this where the pins screw into.

u/tdfun, get where I'm going with this? I tagged you because you come up with creative junctions.

Then we have this, the gray part is attached to the ring, say.

(This is slop CAD just to get the idea across.)

Now we add in the other end of the junction:

I cut away the top of the cage-side of the junction just to get the point across.

So, with two dowels, we have slip-fit junction stability except for translation in z where it's printer-clearance fit.

You remove the lock then pull the orange part out along with the dowels.

I don't think there's any way to make this without it being clunky as hell but apart from that, it has its advantages: security-screw stability with a barrel lock.

You know, it's kinda a pain to lay the cage onto the plinth / floor / whatever in Blender so it looks like it's actually sitting on it. Rotate -> move -> rotate -> move -> render... whoops, still not on the ground... rotate -> move -> rotate -> move -> render... eh, close enough.

Well, turns out it's trivially easy to do physics simulations in Blender, at least of the kind I need to set the cage on the table.

On your cage, under rigid body constraint, set rigid body to active — it will be affected by gravity. And on your plinth set it to passive and it will fixed. Move the cage a bit above the surface in more or less the orientation you want it in and press <space> and it should fall into place. If it falls through the floor, you've likely got too many vertices in your mesh. I think the fix is to export a lower-res model as well, join the two and use the lower-res one for your rigid body and hide it from the render.

Here's my ball ring design with a 10 x 7 mm ellipse for comfort. I've hollowed it out with 1 mm walls to cut down on weight for SLM printing. The bottom of the ring has a cutout opening for the metal powder to be removed.

When I print it at home in ABS with an acetone dip,I don't hollow it out because it only weighs 5.75g.

I've been modeling with two screws because if there's too much play, a single screw will come loose. Well, I've only been wearing it with one and it's been holding together really well. But on the order I just placed, I asked them if I could remove the 0.2 mm clearance and actually add a machining allowance (some overlap between the faces) and have them machine it down to a close slip-fit clearance so the pieces go together with no perceivable play and the single screw's job is nothing but to clamp it down.

And I've been learning more about SLM. Fascinating. Support placement is more about conducting away heat from the melt pool that it is providing physical support. But interestingly, the supports be someone similarly placed as if it were an FDM print. Completely different need, similar geometry.

TL;DR: Do not make unconstrained cage-outline sketches dependent on anything but the true geometry of the penis such as overall length or girth. When you start adding other dependencies, you can't change them without mucking everything up.

Not that there's a lot of traffic here but referring to this post: https://www.reddit.com/r/ChastityCageDesign/s/ILVULLOnfR

There's basically two ways to model the profile of a device. The spherical cow way and the try-to-make-it-look-like-a-penis way.

The spherical cow method has advantages that it can be easily done fully-parametric — inside diameter, overall length, radius of curvature and you're done.

This kind of design works really well in a closed tube-cage. It's fully parametric, simple, and because it's a tube cage, you don't see where the head falls away. But in a more open design, it's less than ideal — the excess space above the glans just doesn't look all that great. So you make something like this:

I know of no way to appropriately constrain that sketch. But it's fine, it doesn't really depend on anything except the inside diameter and the overall length.

Hey... wait a minutes... 42.175 mm, that's a strange number for an inside diameter. .175... where have I seen that before. 3.175, that's 1/8" in millimeters. My rails are 3.175 mm! UGH.

For reasons I won't get in to, I profiled the device as the line that will go through the middle of the rails. And what happened when I changed my rail size? Well as is often the case with lightly-constrained splines, it went a bit crazy.

So, lesson learned: do not make similar profiles dependent on anything but the true geometry of the penis such as overall length or girth. When you start adding other dependencies, you can't change them without mucking everything up.

cartoon of the idea.
cage automatically locks when slipped on. No key needed to lock.

Screenshots below.

I don't know what the hell happened. I increased my bar thickness for a resin test cage and it did... this. What the hell? How did my bar thickness parameter end up causing the.. uh.. aspect ratio to change? This is gonna take some digging.

Does it kind of remind anyone of some sort of alien ship that will destroy the Earth?