Dyne's LD-F1 (D-O concept) build

[Dyne]

I'm currently in the process of rebuilding my model of the droid, mainly so all components are in the same file, to minimize the impact of Fusion's editable file limit.  

In the meantime, I've put some more thought into the neck design.  

This meant revisiting the ambiguity that I mentioned in the last paragraph of Post #1.  The more I looked at the two images of the droid we have, the more it became clear that they are actually showing two different designs for the neck "hinge" joint and the upper stalk arrangement.  Have a look at this closeup:



In the retracted version of the droid on the left, the larger stalk is pretty obviously attached to the center section of the joint, which is somewhat inset from the two round sections on the outside.

In the lifted version of the droid on the right, that same stalk is instead attached to the outer section of the joint.  Also, the center segment of the joint is not inset at all.  Indeed, you could read the joint as having only two sections (possibly with a very thin disc in between), with the larger stalk attached to a sleeve rotating around its section.

It's not clear exactly how the thinner stalk is attached in either image.  On the lifted version it could be on the outer section of the joint opposite the thick stalk, or it could be attached to a thin disc between that section and whatever passes as the middle segment.  I'm not going to try to model the latter idea, but let's call the former one interpretation A:



On the retracted version of the droid, the thinner stalk's positioning is very ambiguous due to the shadowing that conceals its attachment.  It could be beside the larger one, behind it, or both (diagonal from it).  I think I can disregard the diagonal option; mechanically it doesn't seem to make much sense.  The remaining two interpretations, I'm going to call B (Beside) and C (Centered).




What does all of this mean for my droid?  Well, mostly that I have no compelling artistic reason to choose one over another, so I feel free to pick whichever interpretation I think works best.

From a purely practical standpoint, any of A, B, or C are probably workable.  A or B could let one use a linear actuator as the thinner stalk (if you could fit one there) to control the bank of the droid's head.  Putting the thinner stalk directly behind the larger one (Interpretation C) would make it easier to create a parallelogram for making the droid's visible neck lean forward/back, if I wanted to go that route.  Or for stabilizing the head when the droid starts driving.  Or making a nodding mechanism instead of a banking one.

For awhile I waffled on whether I should design a mechanism that would allow the droid's visible "neck" to lean forward and back.  However, this isn't shown in the art and would be a more complex mechanism with additional motors needed, potentially more weight in the neck, etc.  Maybe I'll look at that for V2.

For now, I've settled on keeping the neck vertical and simply allowing it to lift higher as shown in the art and in my earlier diagram.  This is a dummy version of the neck that I've got in mind:




Essentially it's a basic parallelogram mechanism, but you might notice that there's no fourth bar between pivot B and pivot C.

I realized that the actual shape of the four linkages doesn't matter (within reason) as long as they are rigid, don't interfere, and their four pivot points form the vertices of a parallelogram.  In this case, the entire rear half of the droid's body shell rotates around C.  B ties the neck "hinge" to that.  Effectively, there is a "virtual" link between B and C.

If the link CD is kept horizontal, then the link AB also remains horizontal to compensate as AD and BC tilt upwards.  And since the droid's neck is perpendicular to AB, it remains vertical.





The two "pistons" shown as AD are really just decorative and do not actually change length. The lift mechanism is likely to be a small linear actuator of some sort that directly lifts the rear shell of the droid (indeed, there's a small piston-like part visible in the lifted image of the droid, just behind the orange wire).

Because the shape of the linkages in this setup doesn't much matter, the details will likely change (particularly the bit tying A to B).  But this is the basic principle.

[savagecreature]

gotta love concept art.

[Dyne]

As I've mentioned elsewhere, my plan was originally to spend the rest of June finishing the design for LD-F1, then use July and August for printing and building it so I can have it running at Dragon Con.  Naturally, my brain rebelled, as it does every time I try something like this, so I decided to trick myself into getting back to this build by speedrunning some design for 99-99 from Star Wars: Visions (the Ninth Jedi).  That seems to have worked -- after a few days of concentrating on that droid, I'm back in action as you'll see below.  

(That trick didn't stop me from adding costume projects -- plural -- to my list, though.  Thankfully, I prioritize droids and I'm a lot less fussed if I don't get the costumes done, so they shouldn't be too much of a distraction.)

When last we left this thread, I had started working on a rebuild in a single file.  Along the way, I did some experimentation with making the track a toothed belt of sorts, which I commented about back in post #10.  This isn't the final model obviously, it's just the starting point for rebuilding everything I did for the drive and body earlier.



(Now that I've been using it, I think that doing everything in one file was a bit of a mistake, so I might split it up into two -- one for the body and drive, the other for the stuff above the body.  Still an improvement on one-component-per-file but a lot more manageable than a giant list of components and features.)

During my trip to Micro Center this past weekend, I discovered that they are currently completely out of Inland TPU, and I only have enough to print one of those tracks.  I hope they get more Grey back in stock before I need to actually start printing them, otherwise LD-F1 might end up with two differently colored tracks.  I'm probably going to print some test models soon with my (bright red) TPEE to try and figure out what settings I need to get the correct level of flexibility.


In the last post I was also debating the neck mechanism.  I previously used that phrase to describe the external "stalked" neck of the droid and the lifting system, but I've recently been working on a different neck mechanism.  Specifically the three axis "nod, tilt, rotate" mechanism that'll be at the upper end of the stalk.  I'm designing something that's pretty typical of what you'll see on various animatronic heads.

Directly attached to the stalk is a servo with a simple gear to rotate a platform on a set of 608 bearings.  Attached to the rotating platform are two servos, to the left and to the right.  The droid's head is attached to the rotating platform via a gimbal with two axes (pitch and bank), and these are actuated using the left and right servos.

The green part here holds the pitch axle.  There will be another part that actually pitches and holds the bank axle, and a third part that does the banking which will be attached to the head itself.  It would be ideal to have all of the axes coincide with the center of mass of the head, but I'm not sure that's feasible here.



So, if the left servo goes up and the right goes down, then the droid's head angles down from left to right.  If both servos go up, the droid lifts its head, and if both go down it looks down.  Pretty straightforward.


James Bruton has done pretty much the same sort of mechanism in various projects, including his performance robots or the simpler head in the video below, though the details may vary, especially for the rotation.  There are also examples elsewhere on YouTube.






For LD-F1, the entire mechanism needs to be (mostly) concealed inside the droid's head.  The white portion of the head is sized at 10 inches wide x 7 inches deep x 3.68 inches tall (the orange bit increases the depth and height somewhat, but since it is placed asymmetrically along the width I don't count it for our purposes.  

I don't plan on putting much else inside the head besides an SG90 servo for the antenna, LEDs such as an Arduino Neopixel stick, and possibly a servo board.  Still, my mechanism needs to be fairly compact, at least in the height and depth, because the MG-996R servos I'm using for head animation are over two inches long each (if you count the mounting tabs).  Those are unfortunately the two axes that work best for the two front servos.  At the moment they are mounted vertically, but they were originally rotated 90 degrees from their current orientations.  I may return to that layout because the vertical dimension is the most constrained.

Here are the front and side views of the current assembly (the rectangles represent the boundary of the white portion of the droid's head):





I am currently printing some test parts for this mechanism, like the rotation gear and the servo brackets.  Mostly so I can feel like I'm making actual progress rather than just endlessly buying parts and doing CAD.

Edit: I did end up changing the orientation of the servos. My test parts also revealed I hadn't allowed for the servo wires, so the servos wouldn't actually fit in the brackets; I ended up changing to a J-shaped open top design.

[Dyne]

Though things are going a little slower than I would like (mostly due to my focus slipping every so often), I'm continuing to make steady progress, so I don't feel like I'm falling behind.  The head portion is starting to come together, and I still have nearly two weeks to deal with the other challenging bit (the treads).


This is the setup for the portion of the droid above the base, as it exists currently:




The green model is my interpretation of the externally visible neck structure of the droid.  Though it appears to be two independent "stalks", it's really just one part (though I plan to split it into left and right halves for printing).  As I mentioned before, I decided against making the droid able to lean it's neck forward and back, at least in version 1, so having these as one part is perfectly fine.  Still, I put a fake "pivot" at the bottom of the rear stalk.

The stalk model is essentially a printed shell around the primary structural elements of the neck: a pair of 5/16 inch threaded rods.  You can see in the cross section below that the rear rod runs all the way into the head (it's the rotation axis of the droid's head mechanism, and it's 5/16 inch because that's what works with the 608ZZ skate bearings I use).  The forward rod is simply there for strengthening that part; nothing actually rotates around it. For proper strength I'd really need to have these rods threaded into metal bars connecting them top and bottom, but that's unlikely with what I have access to.

Using the rear rod this way does somewhat limit my options. I believe that on the image of the droid in the lowered position, the exterior neck leans backwards by something like 5-10 degrees. This adds a little more of a raked feel to the droid, and would probably slightly improve the weight distribution. I could redesign the green Stalk part to do this, but doing that would mean I'd have to abandon using the rear rod as the droid's head rotation axis ... it would require a bend in the opposite direction for the head portion, otherwise the plane of the head rotation would no longer be level with the ground.




The "Rotation Platform" (yellow part at the top) is fixed to the stalks via M3 screws and is the attachment for the rotation servo on the upper right, as well as having recesses for the locknuts that keep the rods in place.  

The skate bearings that I mentioned above are nestled in the top and bottom of the orange part (the "Neck Core"), which is the part that the rotation servo drives (by gearing).  You may notice that I have combined the head pitch axle bracket (the green part that was in a screenshot in the previous post) with the Orange part.  It simplifies the design, eliminates some fasteners, and allows me to make the arms thicker since I don't need to fit screws between them and the gear.

I have changed the front servo brackets (red parts) to extend over the two tilt/nod servos rather than under them.  The front rod's locknut will protrude slightly into the area these would rotate through and I didn't want them colliding.  The tilt/nod servo horns may end up pointed in the opposite direction (backwards) either for room or to put them closer to the pivot point for the head.

The lower yellow parts are just the outer portion of pivot point A (according to the labels in my diagram from a few posts back).  These outer sections will be part of the AD arms of the parallelogram mechanism for the neck lift.

You can see that pivot point B is modeled into the bottom far right of the green part.  Pivot A will use another pair of 608 bearings, which pivot point B uses a pair of tiny 623ZZ bearings (which are also what I'm using for the pitch and bank axis in the head) because I wanted something a little less blatant than another skate bearing tucked under the forward edge of the rear body shell.


Finally, below is an image of this assembly in the context of the droid, with the upper box representing the head as before, and the circles representing the rollers of the droid's tracks (left is forward).  The construction lines coming off the rear roller are for positioning Pivot D of the parallelogram (C is the axis of the rear roller).  I will likely have to add a bit of weight to the rear of the droid to offset the entire mass of the head being near the forward roller to prevent it faceplanting when coming to a stop.




Because I know I'm going to need to print large pieces for this droid soon, I had to address a few small areas of my print bed that weren't adhering very well (instead of just avoiding them).  So today, I spent a little time re-leveling the printer (it's been moved around a few times since I last did it).  So far it seems to have paid off.

[kresty]

Because I know I'm going to need to print large pieces for this droid soon, I had to address a few small areas of my print bed that weren't adhering very well (instead of just avoiding them).  So today, I spent a little time re-leveling the printer (it's been moved around a few times since I last did it).  So far it seems to have paid off.

I had a similar experience recently.  Printed a bunch of turtle shower curtain hooks.  First batch of hooks had no trouble, but the 2nd batch 1/2 of them wouldn't stick

[r_saggio]

I always give my print bed a quick wipe down with 91% isopropyl alcohol between prints to make sure the surface is oil and dust free. Seems to work every time.

[Dyne]

T-Minus 8 weeks

As I write this, I now have exactly eight weeks remaining to get this build to a functional state (with a week of wiggle room/recuperation afterward before it's time to pack up for Dragon Con).  Things are starting to come together on the design (assuming I can stop breaking the timeline).  My checkpoint for "finishing" the design is this coming Thursday.  

It doesn't really have to be totally finished, because I can wrap up any remaining bits while I'm waiting on the printer.  For example, I calculated that my original rollers would take just a bit under 10 hours each, and there are six of them, so that'll be nearly 1.5 workweeks of printer time alone.  (I've made them shorter now, but still.  Once I get the axle/bearing setup finalized, I'll probably start printing those.  My friend has offered to help with his printer as well so it won't really be a problem for the schedule.)


I have done a lot of work on the upper portion, with the front, left, and top of the head and the antenna almost completely modeled.  (I get to make up the rest of the exterior because it isn't seen in the art.)

One idea I briefly toyed with was giving the lens a holoprojector-like mechanism, but I decided that was a bridge too far.  I am, however, still planning on having the antenna raise/lower via servo, possibly have an LED on the tip, and I'm strongly leaning toward making the panel on the top of the droid's head open.




I've also got what I hope is the final design for the head animatronics (assuming that they don't require further revision after testing).  I made them more vertically compact, which will help get the axes for the head rotations closer to the center of mass.  (Speaking of mass, when I weighed one of my earlier prototypes, it came in at roughly 327 grams.  That bit of it is probably slightly lighter now, but there are also now a few more parts.




In Fusion, it looks like the mechanism is clear to get roughly 58 degrees of rotation to either side before the parts might collide with each other, for a total of 116.  I'd love to get 360 or even 180, but that would require a complete redesign so that the rotation servo is either fully above or below the rest of the mechanism, and there's not a lot of room in here.  On the pitch (raise/lower) axis, I can probably get around 25 degrees from horizontal in either direction (a little more when pitching down), and I believe it's capable of tilting the head to either side by 15 degrees.  

These limits may need to be adjusted once I see whether anything is interfering (e.g. whether the head itself hits the mechanism or the stalk; or when the servo horns are rotated down too far , they may hit the rotation platform or screws if the head rotates).  After I print the latest version of the blue tilt arm for the animatronic assembly, that will hopefully be ready for a real test.


I am not neglecting the body of the droid ... the chassis CAD is a bit behind schedule, but I've done the placement for the motors and so forth, worked out some of the mechanics for the lift system, and rebuilt some of the aesthetic work from my draft model.  I also started feeling like 5 inches for each track was too wide to match the proportions of the artwork, so I reduced it to 4.5 (shortening the rollers in the process, as mentioned above).  Here's a comparison of the old and new proportions...








Side view with placement of lower lift arms.  Looks like I'm not getting away with a full body axle on the middle wheel.




Most importantly, however, I have already begun printing and testing, which I wasn't scheduled to begin until next month.  I've already made a rig to mock up the drivetrain (at least motor and pulleys, controlled via PS3 Nav controllers by Penumbra on one of my ESP32s), and printed the associated belts, which work fine after cleaning off some of the stringing-induced blobs.  I'll need to reprint them to change the diameter, but I'm confident they'll work.





I have also printed the first major externally visible part (the stalk section from my previous post) part and performed a dry fit, complete with the threaded rods and the head servos.   It's a pretty beefy part once the rods are installed, with 5 perimeters.  Once I cut my threaded rods down to the correct lengths, I can begin the real assembly and preparation of the part (it will be a pain to sand smooth).  



I was going a bit too fast on that print on the upper end, I think.  I've slowed it down since then.


In terms of the upcoming schedule, I tend to write my "checkpoints" for Fridays so I can triage the preceding tasks on my days off if I need to pick up the pace.  This is what it currently looks like:

• 2022-07-01 - Checkpoint: Begin printing (I'm slightly ahead of schedule on this)
  
• 2022-07-08 - Checkpoint: Print the treads! (They'll take a long time and I have to get the size and tooth profile correct.  Which reminds me, I need to get on ordering additional Grey TPU.  Micro Center is still out, but I have an alternate in mind.)
  
• 2022-07-15 - Checkpoint: Begin assembly and wiring (technically I've already started this)
  
• 2022-07-22 - Checkpoint: Finish printing (at least the big stuff)
  
• 2022-07-29 - Checkpoint: Begin testing
  
• 2022-08-05 - Checkpoint: Begin painting
  
• 2022-08-19 - Goal: Fully painted, tested, and assembled
  
• 2022-08-23 - The final week before con begins.  You should be done by this point so you can rest.
  
• 2022-08-26 - Last weekend before con.  Get anything big done NOW!
  
• 2022-08-29 - Absolute last day for droid building
  

Busy Busy

[Dyne]

T-Minus 6 weeks (minus two days)

So I've been busy churning away.  I've pretty far behind my projected schedule because I haven't even completed the design, which should've been done two weeks ago.  It is slowly coming together, just not fast enough for my liking.

Part of that is due to losing some time for health reasons (just the need to sleep and the occasional headache from staring at and thinking about CAD all the time), and part of it is just my sporadic energy.  But part of it is because I had to face up to the need for a major design change.

Specifically, I have switched from the printed flexible belt treads because my early tests indicated that I had some errors in my design and also that the chances of finding the correct combination of flexibility and other settings would require a lot more time than I have left, as well as convincing me that the chances of getting a good clean print of both treads were low.  I was having too many issues even on the small test prints.

Instead I began what I should have done from the start: design a proper tank-style track.  The art has always suggested that, but I've previously discussed why I didn't go that route.

Since the droid's parameters are relatively fixed, I wasn't about to try and kludge it around a commercial track drive frame kit (which are pretty expensive anyway).  But since I only vaguely knew how to go about designing a track system, I did a bit of research from makers I know of that have built such a thing.  James Bruton.  RCTestFlight.  Various Wall-E Builders, like Matt Hobbs and Mike Senna (see his video on designing the tracks, for example).  

Ivan Miranda had the biggest influence on my system, though.  I've been watching his channel for a few years, and he's done several tanks over that time.  The most similar to what I'm doing (in scale) was the RC Mini Tank that he did in 2020. LD-F1's tracks are heavily inspired by this (but a bit larger).



Those were some of the earlier iterations. I'm currently on V5, which I am calling final. It differs mostly in that it has longer pivot pegs, and is therefore narrower and has one fewer interlocking hinge section on each side, and a slight slope just inboard of each sprocket in case the track somehow tries to get off center (to nudge it back).




Having made the decision to switch, there were still issues to address such as trying to get the correct look. As I've mentioned before, the art indicates roughly 18-20 segments on each track.  Part of why I went with a belt was because doing that with a track is impractical on a droid of this scale (at least, it is if you don't want the droid to produce a lot of noise and vibration).

That's because dividing this length of track into only 18-20 segments would make the pitch between the ends of each segment greater than 2 inches.  Consider that the drive wheels are themselves only roughly 4 inches in diameter.  That means their circumference is 4 pi, or a bit over 12 inches.  In approximate terms, if you want to fit a regular polygon with ~2 inch sides into a circle with a ~12 inch circumference, your polygon will have -- at most -- six sides (12 / 2).  Can you imagine driving a droid on hexagonal wheels?  Budumpbadumpbadump.

So you need many more segments than this to make a smoother approximation of the drive wheel.  More than twice as many as the art, probably.  So I considered linking two or more rigid-but-jointed links with a single flexible traction pad to help make it appear closer to the artwork (they're the red ones in the picture earlier)



You could maybe do this, but you have to make one attachment for the pad as a pin in a slot parallel with the direction of travel, rather than a pin in a hole, because as the traction pads go around the bends in the track, they must traverse a greater distance than the links they are attached to (being further away from the center).  



The slots allow the pin in the slot to slip further away from the pin that's just in a hole (or rather, the pad itself moves further away relative to the pin that's in the slot).  Since the slot is parallel with the track, the pad can only move in this direction, and is constrained from getting further from the link it's attached to.  The result being that the pad is somewhat bent around the curve.

At least, that's the theory.  In practice, the pad has a tendency to bow upwards on the edges of the track, so you'd have to bias the curvature (my idea was to do it by making the infill consist entirely of a couple of solid lines that run across the pad's length from the inboard edge of the track to the outboard edge, so it's more rigid across the track's width, and more flexible from leading edge to trailing edge, but I never tested that).

Also, because the links need to be fairly narrow (mine are currently 21 mm) there's not much room for the slot without compromising the link's integrity.  Nor is there much room for pin (screw) installation or removal or for having more than two attachment points per link across the width of the track.

So I abandoned that idea for v1 of the droid, and just went with 1 traction pad per link.  I may even print most (if not all) of them in rigid plastic like the ones below.  They are mostly aesthetic parts now to make the tracks vaguely resemble the art.  



They don't really have to be flexible to follow the curvature anymore, and if I mix rigid and flexible pads, I can fine-tune the friction of the tracks by adding or removing flexible ones.



Also, the rigid parts print faster, which is kind of important since the links alone take roughly an hour each, and even the rigid traction pads take about 45 minutes each.  I need a total of 106 of each.  Luckily a friend offered to help by printing any parts that will fit on his Elegoo Neptune 2.

I may go into the process of designing the track system later, but if you are curious, I ended up with these parameters:

• Link Pitch: 21 mm
  
• Total number of links per track: 53
  
• Total Track Length: 1113 mm (53*21)
  
• Sprocket Teeth: 14
  
• Sprocket pitch diameter: 93.78 mm (this is the diameter of the circumcircle of the regular 14 sided polygon formed by the link pivots when fully engaged with the sprocket.  In other words, it's the diameter of the circle that all of the link pivot centers would pass through as they go around the sprocket.)
  

The most useful tidbit I came across was the formula for the sprocket pitch diameter.  Given a certain link pitch (P) and number of teeth (T), it's:
(P/2) * csc( pi / 2T )


Since fusion doesn't offer a cosecant function, you can't use that directly.  Luckily the cosecant is just the inverse of the sine function. The result is more like:
( Link_Pitch / 2 ) * ( 1 / sin(( PI / ( 2 * Sprocket_Teeth ) ) * 1 rad) )




Besides the track system, I've also done a lot of the modeling for the head (doors and attachment points and such) and I already printed the smaller section, wired up and tested most of the head LEDs and my ability to control servos via i2c, and tested the head animatronics.





Left side LED and head attachment screw holes (to be covered by orange stripe panel)




This is a test print of the left side of the face, upside down.




The full head mechanism and upper stalk.  I've since printed the four pieces of the lower stalk arms (green in the CAD) and tested them.




I need to finish a few things before I can print the other portion of the head, but I'm saving that until I can wrap up the body and tracks.  A tank droid you can drive around at a con is more entertaining than one you have to carry around.


I've been pondering how or if I'll work R/C in as a second control system. I've also finally gotten (edit: and successfully bound) a receiver for my FrSky Taranis Q X7 radio transmitter.  Awhile back I bought a Jumper receiver, which should've been compatible, but I had trouble making it work with FrSky's firmware shenanigans.  The new one is a FrSky RX8R. Still had to play with the firmware, but mostly to fix what I'd done trying to get the Jumper receiver to work.

I'm not entirely sure how I'd to go about integrating R/C, but I suppose I could just poll the receiver's servo outputs via the ESP32 and use those values whenever there's no PS3 controller connected. I could also go find an SBUS library and try to read the servos that way. I may want to use SBUS for telemetry feedback to the transmitter anyway.


I've waffled for a long time on what to use for the lift system.  A standard linear actuator is much too large to fit in the body, and the ones that are small enough are pretty costly, so I considered going with a DIY version, such as one based on this design by Michael Rechtin.





But then I would've had to spend time modifying it to fit the build, testing the mods, etc., and I would've had to gather all the components as multiple unit packs as well.  While individually the price of the DIY version is much cheaper, the combined price of buying the parts to build several of them is a significant fraction of the price of the off-the-shelf solutions.

I eventually decided to go with a Hitec Linear Servo from Servo City.  This single servo is the most expensive part by far on the entire droid, but I think it'll be worth it.  I got the HLS12-50100-6V ... 2 inch throw, 0.6 mm/sec speed (so roughly 4 seconds for full travel), 11 pounds thrust.  I don't know how much the head will end up weighing in total, but the neck stalks and big head servos shown in the photo above are most of the mass, and that stuff probably tops out around 1.5 to 2 kilograms (3.3 to 4.4 pounds).  

The servo is small enough to easily fit in the droid, is HOPEFULLY strong enough (probably is, as far as I can tell based on the rating while only guessing at the final total weight it has to lift), and is not ridiculously slow.  It also has decent holding force when unpowered, which is useful.  And in contrast with a linear actuator, a linear servo can be given a specific position to go to, rather than simply saying "move to the other end stop.  Now move back to this one."  That's useful for puppeteering, though I doubt I'll have time to code this in for the initial run.

My remaining concern with the lift system is making sure that the rear shell of the droid (which is one arm of the parallelogram that forms the lift system, as I've previously described) can carry the load.  I'm considering putting aluminum sheet under the printed exterior to bear most of the weight.  I'd hate to go through all this trouble and then break the back of the droid at the last minute.


I'm too tired to add pics or anything right now, so I'll come back and do that sooner or later.  (Edit: Done)

[savagecreature]

Wow. This is a pretty fun and exciting (if taxing for you!) build! I'm loving watching this come together and can't wait to see it.

When i was reading the above post and you mentioned how it looked "in the art" I immediately thought "the final product is very, very rarely exactly like the concept". I guess all I'm trying to say is don't be too hard on yourself if the requirements of making it a real droid that actually 'works' forces you to change aspects of how it looks in the concept art.

[Dyne]

Wow. This is a pretty fun and exciting (if taxing for you!) build!  I'm loving watching this come together and can't wait to see it.

When i was reading the above post and you mentioned how it looked "in the art" I immediately thought "the final product is very, very rarely exactly like the concept". I guess all I'm trying to say is don't be too hard on yourself if the requirements of making it a real droid that actually 'works' forces you to change aspects of how it looks in the concept art.

Thanks.

Don't worry. At the end of the day, I'm not actually all that fussy about complete accuracy to established props, much less to concept art.  I do put in some effort to make it look good (which is what you're seeing me muse over here), but if I need to adapt things for practical reasons or just want to change things to suit my own tastes, I'm pretty content to let close enough be close enough.

I did some of that in my BB-5M build, for example, which was based on one of Christian Alzmann's BB-8 concept art domes, but after a certain point, I just outright altered or replaced some of his features for my own preferences:  Replaced the PSI with something akin to R2's fiber-optic front logics, made up a three LED PSI wholesale in place of the large "comms box" on the side, altered the antennae just because I had some greebles that would've looked fun, etc.


Note: I've just edited several images into my previous post.  Buildwise, I printed sprockets for an old version of the tracks and a small section of track to make sure the pitch is right, and I've moved to trying to crank out links and traction pads for the tracks now that I've more or less finalized their design. I'm making a push this weekend to try and get most of the body/chassis design done so I can get those parts printed and make a start on getting this thing put together soon.