Is Scale Inaccuracy a Cardinal Sin?

Is scale inaccuracy a cardinal sin?

3D Printing has limits, some quite strict limits, I'd like to add; Shapeways' most detailed material (Frosted Ultra Detail) has a lower detail limit of 0.1mm, yet in N gauge I've struggled to model the wheel springs underneath the Metropolitan Twin Brake Van – I had to resort to stepping the springs into the sides to give the illusion of a multi-layered object.

A fine solution to a pervasive problem...

Probably not the best example given I've added no primer, but if you squint...

It's not just simple resolution either, definition is also a problem.  The Shapeways minimum detail level of 0.1mm is actually made up of four 0.025mm laser pixels in the printer; this is to ensure the position of any details that small will be reasonably accurate, which they are.  However, this means that if you go this small (as anyone has to if they deign to model N gauge), there is a 25% directional variation in the X and Y axes (god forbid both!).  The upshot is that your “super-fine detail” will often have poor definition, giving it an almost abraded look; to make matters worse, Shapeways uses Netfabb Professional to nest the models in the most efficient way possible, which will allow the most models into any one printing operation – This means your magnum opus could be printed at all kinds of unfathomable angles!

Looks like it hit a sandpaper block in a hurricane!

Let me introduce you to what is on the left:  That is a mid-2000s model of a Class 08 from Graham Farish.  It clearly displays all the hallmarks of the early chinese production (apart from the split gears, thank god!); This one was evidently designed in Poole and thus can trace it's roots back into the 90s at least.  The major manufacturers in N, Peco and Grafar, had some pretty low standards of detail compared to what even Hornby was capable of at the time, a fact I can verify by way of a 2005 Hornby Catalogue.  N gauge at the time was only slightly better than what FUD is capable of today, as can be examined below:

Circa 2005 I believe, got it as a birthday gift :) 

To examine models, I like to ask “Could this model be blown up to full size and be switched with the original for a few days before being noticed?”

Lettering is in an examplary state for the time, but as you'll see in a minute, still a bit wibbly compared to modern efforts

A bit wide, perhaps,  though if gave it a suitably proportioned etched grille, all but the most eagle-eyed would give the nod

Grafar ought to be proud for making it's 08s look like this in N!

What can be ascertained from an inspection?  Pretty much all moulded handrails with not a wire in sight, no cab glazing, it's clear that most of the effort was focussed on the lettering and other lines (which are still a bit too watercolour for my taste).  A folorn state when compared to the OO gauge models of the time, and sadder yet when you consider how even wagons have progressed in this day and age:

Lettering is razor-sharp even when weathered

Rail-Thin details all over from 2013

Underframe Pr0n :D

Yet in spite of all this progress, the Grafar 08 still has the basic shape of an 08 right, there's very few things about it that can't be fixed by detail etches and added handrails; even advances in adhesive technology such as the glue 'n' glaze can provide a superbly simple solution to it's window-related ills.  I think our attitude towards N gauge back then speaks less about the potential for psychotic levels of detail and more about the amount of effort we'd like to put into it, not to mention the comparison point of OO gauge we had back then.  If it weren't for Grafar moving its manufacturing to China and subsequently re-invigorating their models in a big way, N gauge would have indeed become a fairly large cult gauge, full of fanatical wizards etching and bending and soldering their way to victory.

Today, we've reached the point where unless you're doing a strict time and place – and thus need to re-number rolling stock or add appropriate dirt (such as china clay operations) – chances are an off-the-shelf model can be plonked on your track as-is and look great.  The kits of today are excellently appointed too, and with advances in design and tooling, they're not hernia-inducingly hard to get right.  The main case for improving detail is in the 3D Printing sector, as well as the material properties to make a decent chassis.  Let us further peruse The Metro Twin Brake Van:

Details are a bit dulled by the black paint, makes me sad indeed :(

A clear progression from right to left, though my Metro Twin Brake seems to have sprouted fluff whilst in storage!

If anything, comparing 3D Printing to these models has made me realize something about my craft:  with 3D printing in it's current state, it is essential it looks good out of the box – the fragility of these models is easy to underestimate if you're it's daddy and you're handling it like a baby, but real modellers won't care to be so careful.  The 08 has superior definition to the Metro Brake, of that we can be sure.  The details are also cast in metal so it's far more durable, and therefore more receptive to re-working.  If you play the cards right, you could probably turn this 08 into a reasonable representation of the real thing, as long as no recent Grafar models pull up alongside, of course!

So is it right to expect surgical precision?  Could an obsession over micrometres really have spelled the end of an entire scale?  If you ask me, it all depends on context:  Ask a Shapeways modeller to re-create the modern Grafar 08 and... he's fled!  Too much in the way of technical hurdles and that's before we even attempt to recreate the etched ladders and fitted handrails.  Perhaps this is why 3D Printing is the preserve of the most obscure wagons - wagons that only exist in highly-researched books on quirky and largely forgotten avenues of railway history.  An admirable intention, to effectively catalogue all of our railway's forgotten history in model form, but if you want a hand at this yourself, I recommend sticking to OO where you can fall back on WSF (Polyamide to other companies) and still have a reasonable amount of detail; N gauge 3D Printed rolling stock has yet to come of age, but I'm confident it will in the next 5 years.

Consider the Madder Valley Railway (Vid here), it's models grind and groan as they traverse the layout, and the style seems to make no sense with Beyer Peacock locomotives hauling distinctly American coaches; but it is a true survivor among layouts, it's visual appeal has failed to be quenched even as it's flock materials fade in colour and the wheels look comically disproportionate by modern standards.  This is how we ought to treat the hobby, not as an egotistical scoreboard, but to approach it with the aim to create an atmosphere; to immerse the viewer in a frozen sliver of time, or even just to amuse them with quirky cameos or even mechanical functions!

As for the debacle over “The end of N”, it was right to condemn Grafar for a lack of progress; you start a company to pool resources, to purchase industrial tools and manpower to surpass what an individual modeller can be expected to achieve.  The old Grafar 08 strikes me as a model that could have, potentially, been cast by an enterprising modeller in whitemetal.  My point is that we should not let detail take hold of us like money does to some people, because it produces the exact same sad result – a loss of humanity accompanied by a loss of compassion (we all know the rivet counters, do we not?  Who likes their company?  Silence...)

To follow your heart, is it worth losing your mind?

Charlie, I think we're on the wrong branch... A confessional

As I write this on the train to work for the first time (coming up in the world ;) ), I'd like to reflect on the possible directions this blog could take; for the 5 people who know this place exists, anyway.

As you are no doubt aware, my SLA 3D Printer is taking a god-awfully long time to come to life, partially because of life concerns (my main PC upgrades being a prime example), but nonetheless, i'm beginning construction proper.  The frame members are complete, ready to join and looking pretty good considering this is my first time with an angle grinder!  The Plywood Panels are ready to be assembled as required and accept paint.

Another thing that constantly nags my attention is the fact the virtually no progress has been made on the Shapeways side of Tawe TMD; there are several reasons for this, but the main offenders are:

1. Material Properties – WSF (polyamide) is tough enough for a model railway wagon chassis, but produces lesser detail than early 2000s N gauge models, I.e, the period where it was seriously mooted that this scale was dying!  FUD is acceptable, but far too brittle in tests, with W Irons and springs falling off only enough force to bruise a gnat.
2. Service – Shapeways is under heavy strain right now, it's a new startup riding a technology that is a newborn amongst giants.  These are not a good combination for rapid delivery and processing, with minor changes in models taking 3 weeks to be delivered and a further week for testing and modification.
3. Research – Diagrams of the ancient wagons I intend to populate my Shapeways store with are hard to come by, and when I do finally find them, they’re often fuzzy with poor detail.

1) is unavoidable for the time being, we'll need newer technologies to print more useable materials before I can seriously consider making entire N gauge wagons (chassis included!) in a 3D Printer. 2) is up to Shapeways to sort out, or If another company can sort that out I'd love to hear about them :).  3) is a bitch, but not entirely unsolvable in many cases.  With regards to my current 3D printed wagons (the Metro Brake and the Rigid 8), I'm sorry to say that these wagons are suspended for the time being, while it's possible to make decently detailed models, 3D Printing really has to catch up strength-wise before I can consider selling them as a serious product.  I may consider a hybrid approach of etches and 3D prints, as EtchedPixels seems to be getting on quite well with, but I'll need to learn my way around brass etching first and my first attempts are a stain on my modelling career that shall never be spoken of again.

Somewhere, Bob Symes weeps for future generations...

In other news, I will be visiting the British Festival of Railway Modelling in Doncaster on the 7^th of February.  I've never been to either Doncaster or this particular show, so it ought to be fun on both counts.  This neatly brings me to another announcement – There shall be reviews on this blog!  Oh yes, the time has come.  Given that I now work hours slightly worse than 9-5 (8-6, though I get an hour's lunch in which to write features, or bilge if you refer my personal blog), I'll probably examine smaller products for more intimate reviews; things like whitemetal kits, brass kits, 3D Printed wagons and static objects.  I'm itching to sample the state of our hobby's 3D printed items firsthand, even the best pages don't tell you much about things like ergonomics (for things like handles), surface quality and ease of construction.

As for features, I'm not sure they'll come to prominence for a while.  I am only 23 in a hobby dominated by retirees, retirees who can drop the hammer and call me out with their all-spanning experience!  That's a funny thing about Railway Modelling, it's probably the only industry I know of where you can survive by being stubbornly old fashioned - many business are still able to survive on mail order alone, Dean Sidings being a prime example, and their Pug conversion for the hornby 0-4-0 got a feature in Parker's Guide (a smashing modelling tips publication from Hornby Magazine).  My thoughts are along the lines of ideas about the state of the industry and where we can go from here, and some things damn well need to be dragged into the 21^st Century!

In spite of the ageing demographics our the hobby, I am confident that it will survive, if only because Heritage Lines remain National Treasures somewhere between Stephen Fry and Spitfires.  Despite all the dreadful rhetoric of the “breakdown of family values”, there are still a great many people not quite so blemished, and can thus appreciate there's more to life than power over others.  I picked up a leaflet about that National Model Railway Museum at Ashford at a show, and I can understand why people may be worried by the line “think about the future of our hobby”, but rather than see terminal decline, I see the opposite – I see people looking out for us and ensuring we don't fade into history like a thief in the night.  In short, I see...  Immortality...

Okay, maybe a little too high on myself there...

SLA 3D Printer Project Log 11: Lasing on a sunny afternoon...

Exciting news on the making front:  my Laser Cuts have arrived!  Before I've even finished cutting my Extrusions (I'm a horrendous procrastinator), CutLaserCut of London have furnished me with 6mm Plywood Panels for the exterior; These parts have an almost psychotic precision to them - I drew these in Sketchup which draws Circles as slightly smooth polygons, and every face was sharply defined on even the smallest curves, running my finger over them felt like a D20 would if you felt it with your foot.

I reckon on a little show 'n' tell:

Clockwise from left:  Rear panel with PC Case and 180mm fan in place, Top Panel, Bottom Panel.

As you can see I stuck to fairly simple shapes for this, with lots of holes for the M4 bolts holding the panels on.

Left:  Front Panel; Right:  Both Side Panels (they're identical)

The Oblong bevelled holes are for the access panels which are to be made out of Fluorescent Acrylic (these absorb UV light, cuts out light pollution from external sources).

Another shot of the rear panel with rear-mounted equipment in place.

Of course, the fans will be internal and behind fan grilles once I assemble this thing, but the PC will remain external for access and cooling.

Misc Accessories, parts which make up things like the build bed (bottom left) and the Z carriage upper plate (top right).

The only problem I can see so far is the fact that many of the panels have warped, as can be expected for such thin plywood panels of this size.  It doesn't matter for parts other than the Z Carriage and possibly the Top Vent Cover (the rectangular plate with curved corners and all the cut-outs in), so I think I'll use Aluminium Angle bolted to the Carriage to ensure a level fixture for the Bearings and Threaded Rods driving the Z Carriage up and down.

"Why not use more plywood, or just glue on some Straight Scrap wood?"  Wood has a fantastic Strength-Weight ratio, especially Plywood, but ultimately while it can be very stiff, it is not that strong overall; The parts I use to stiffen can also warp which takes me back to my original problem.

Whew, an enticing delivery indeed, a glimpse into the future form of my Printer; just to end it on a high note, let us view this ultra-cute image of my bodged projector perched on it's mounting plate:

So far I've logged more hours watching youtube videos on this thing than it would be used for roughly 100 small prints!

Stay Industrious.

SLA 3D Printer Project Log 10: It's Extrusive!

Aluminium Extrusions...  How could I have missed you so?  Such a simple way to build up frames, especially for prototypes; here I was about to spend £400 on laser cutting plywood into a rigid frame, as well as £160 for 3D Printed parts!

Advertising my stupidity is a good way to begin a post, no?  Just to prove the opposite, I'll divulge to you what I've got in mind thus far:

A fairly basic crate :)

As can probably be seen in this image alone, Aluminium Extrusions are essentially the Lego of the garage hacker, allowing rapid construction of non-standard frames and sub-assemblies by way of nuts which fit into grooves in aluminium bars, with bolts then holding it all together.  Compared to the previous laser-cut plywood design...  Actually, why not invoke an excuse to use bullet points rather than actually write?

Goods

• Rapid addition of any newly-required features
• The Projector Crane can be an integral part of the frame for additional strength
• Plywood parts can be cut by hand - superb precision is no longer needed since it is automatically attained by a precision-manufactured metal framework

Bads

• If a casing is used (as you can see, it is), you may have trouble upgrading to a bigger projector
• Design is largely limited to right-angles

Not much on the bad side, eh?  Pity it's far from finished - the build-bed requires extensive re-working since I plan to only use laser-cutting for the Resin Basin (this part needs to be made so well you'd think I cast it whole) and I need to model all the brackets I'll need to assemble this thing.  All in all, not bad for a rediscovery made possible by a discussion with a colleague at work :)

Until we meet again...

How to reduce STL errors: Get your 3D Printed items error free for Shapeways

We've all been here, red faces flagging up all over our models thwarting our attempts to produce consistently printable models.  Just to emphasize how annoying this can get, here is a screenshot of my Caswell Flats STL just after export from Google Sketchup:

Just you wait until you introduce curves into the model...

See those red areas?  Those are degenerate faces, and they can do much more besides making the model unsightly, up to and including causing a non-manifold model - all 3D printers require the model to be "watertight" or manifold to print, that means there must be one consistent shell.

Having gained much practice in handling STL files, usually through frustration, I thought I'd put it to use by outlining these three tips to flush out the degenerates and, better yet, prevent them from happening in the first place:

1.  Get Netfabb

Let's face it, computers being computers, no CAD program is ever going to produce a perfectly error-free *and* a detailed, high-resolution model first time (even if such a program did exist, the cost would be horrendous); enter Netfabb - a slick, attractive application that makes light work of banishing the reds.  The Basic version is free to download and use with no time limits, and it fixes most errors with automatic ease; it is, however, limited to the most basic of STL sins and cannot, for instance, Wrap Part Surface which reconstructs the shell of a model to close up the holes.  For £200 you can upgrade to Netfabb Private, which allows access to all the tools you'll ever need to fix STLs (I personally cannot comment on their effectiveness since I only use basic, still, one for the future investments list).  There is a hideously-priced Professional version costing 1500 Euros, which I'd only suggest if an automatic nesting algorithm sounds vital to you.

2.  Reduce the resolution of your models before exporting to STL

Not a sure-fire fix, but one that can get your models from 'RED ALERT!' to 'that'll do'.  Resolution pops up in many different ways, for instance Creo Elements Direct (which I strongly suggest you get if you want to model curves) features an 'Facet Accuracy' setting, accessed via Right-Clicking the Part, selecting Part Properties, then the Facets tab; This will give the option to set either the minimum distance or angle the model will be permitted to render.  This is the result if I go for the insane resolution of 0.5 degrees:

Aside from bringing my new AMD R9 290 Graphics Card to it's knees, this is what 5244010 triangles and 250mb of Chassis looks like.

So you're thinking it's not too bad, except that 73 shells and 144 holes are produced...  Netfabb ran out of memory trying to fix it (silence...).

Let's go down a gear to 1 Degree and see how it is:

Errors around the Pinpoint bearing holes are reduced :)

The repair I tried in Netfabb Basic did little if anything to reduce those lines, although this exercise illustrates a point:  Reducing the resolution not only rids you of reds, but it also reduces strain on your Graphics Card as it renders the model and it makes smaller files with the 1 Degree file being 67.6mb.

3.  (Sketchup Users) Use Solid Inspector

Sketchup hit the spot for many modellers when it introduced it's extension warehouse, myself included - trawling the internet for obscure, often poorly-optimized plugins is now banished to the past along with floppy disks and those chirpy modem things.  One of these plugins to come to our rescue is Solid Inspector, a straightforward function which highlights any issues with Sketchup models by circling surplus lines with orange and holes with red:

This is a rather severe example, but you can hardly blame us when you take the Tumblehome into account.

That was the body of No. 394 of the Chesham set of Metropolitan Bogie Carriages, at which me and Matt Wickham at Bluebell Model Railway (click here for some video of the carriages running) have been beavering away on for some time; Admittedly finding the actual rogue lines and holes is still tricky since the circles don't always scale to your viewport, but as a general indicator it's a godsend which can mean the difference between printing and self-inflicted pain.

The Takeaway:  3D Printing, not 3D Perplexity

There may well be other methods I have failed to mention, but I can sum this post up thus:  Don't rely on your eyes to find faults.  A CAD model, unlike your hands, CNC machines and even reality, can scale down into infinitude, theoretically to the Planck Length and below; that said, god help you if you want to zoom back out again!

SLA 3D Printer Project Log 9: Call me tight-fisted...

Been almost a god-forsaken month since I last posted on this!  Usual excuses apply - work, tiredness and other priorities.  Regardless of this, I am proud to present a completed model for the SLA 3D Printer!

Mostly Plywood construction to keep 3D Printing costs in check.

As much as I'm tempted to excuse the lack of RAMPs Board and some of the hardware (nuts, for instance), the simple fact is that I couldn't be bothered...

This is where the action is - looking down on the print bed with the beam set to 12.8 x 8.0 cm build area.

With this simple design in mind, let me take you through the DXF files for the laser cutting, which should hopefully let you know just how much goes into things like this:

25346.8mm of lasering goes into the 6mm ply parts ALONE.

Looks refreshingly simpler, but these 12mm ply parts still need 25260.6mm of cutting.

Finally, 12mm Cast Acrylic makes up the basin with a mere 8290.95mm of cuts.

Some of you may be thinking "Gee, that's sure to be expensive with all those finger joints and details" - how does £400 inc VAT sound?  Sure, it's a major expense, but would *you* consider doing this by hand?  All I need to do is persuade my ego to let go of that 4K monitor for just a few more months (not gonna happen ;) )

If you've read this post over at the life blog (to hell with re-writing the name here, that pubescent cacophony of letters needs to change), you may notice that I am aiming for change in the coming months not just with my blogs but my whole life - things are getting quite heavy for me and I need to re-tool.  The basic gist is that I am trying to do too much and it's driving me insane to the point where I just dive into PC Gaming and get nothing done, so a few things may have to come and go.  This project is here to stay (why not cut out the middleman for minor detail/operation changes?), but I'm looking into other avenues to try my hand that may eventually make me a decent living if I can pull it off correctly.

Finally, all my blogging is now on here, (pubescent jumble blog) is now mothballed.  Hope to see grasshopper-minded adventures on a much grander scale once this bridge is crossed.

Stay Industrious...

SLA 3D Printer Project Log 7: Underframes? Thought I did those in Creo...

I've been working on underframes, I know, it's a bit soon to resume work on the wagons but I'm on about the mounting system for my 3D printer; until now I had components floating in space - not an ideal proposition for accuracy.  That has now been fixed, and I was in for some wake-up calls.

Don't worry, there'll be 10mm bolts holding the basin in place.

The dimensions were envisioned as a worst-case scenario of 1m³, which would give me plenty of wiggle room to add insane features like gull-wing doors and water-cooling for the built-in pc, but the dimensions as they stand now are 412mm x 380mm x 626mm.  I reckon I can now aim for a desktop model, and this means a few changes:

• I'll probably ditch the case, and just use a black cover when not in use to prevent the resin from curing - this will probably save me a lot of bother when maintaining my printer.
• A Mini-ITX PC is essential - I can no longer use the bulk of the unit to house an ATX motherboard.
• Get more sensible with the design - I (and possibly you) am going to use this printer frequently, I need something serviceable.
• Mounting the touchscreen just got a lot harder...

A few ancillary developments have happened in my life recently; I've got a new job at a composite manufacturer running cure checks for them, and one of the things I observed is that the Autoclaves run standard PCs alongside their massive built-in computers to run the UI; maybe I shouldn't follow the leader, so to say, but it gives me reassurance that my plan to use an x86 PC to control this thing isn't insane after all.

As much promise as the Pi had, I am not a coder, and Raspbian didn't run how you'd call slick (Risc OS did, but it doesn't support wireless internet which makes things a hell of a lot harder these days); if I'm going to use it everyday, which I may do for a few weeks of each quarter, I'd prefer a rapid system as well as one which has a GUI.

I intend to install Windows 7 Basic to run Creation Workshop by PacManFan, a program which can slice the STLs as well as operate the printer with the help of RAMPS board.  This program uses little CPU power, so the Pentium E2160 I possess can be used (I bought it for a secondary gaming rig, to use whilst home from University), but it does use a lot of GPU power in it's Model View, which runs on OpenGL; I bring up OpenGL because it means that Workstation Cards, designed largely for OpenGL-accelerated CAD programs, could give stellar performance.

I'll expand upon this further when the time comes, I'm getting tired in one of my few windows of time I have to do CAD and blog, in spite of the much-needed money.

Regards.

SLA 3D Printer Project Log 6: The Up of Sketch

Creo Elements Direct is fantastic, it's similarity to Pro/Engineer and Solidworks make it an instant transition for someone in the CAD industry that's used something less archaic than AutoCAD and it basically operates on an Additive/Subtractive modelling principle rather than vertices and points like the free version of Sketchup (Sketchup Pro has Solid Tools which afford the same functionality, but costs $590 or ~£350 at time of writing).  Model Railway wagons are a no-brainer using this method given how many rivets and tumblehomes and other assorted chamfers and blends make it impossible to attain high resolutions under Sketchup.

However, It's use as a design tool for machinery like the SLA 3D Printer Project and the Reprap is severely curtailed by it's lack of visualisation features and it's very modelling system:

Initial design for the Resin Basin, made from 12mm Cast Acrylic.

As can be seen, it's a grey box with a flange, not even remotely looking like the clear acrylic intended for the production model; I also wanted to raise the flange to a level where the top of the flange will be at resin level, allowing me to make a 12mm Calibration Sheet to place in the mount to calibrate the projector - in Sketchup, this is as simple as selecting all faces you want moved, then raising them to the required level, whereas Creo will need you to delete the part, raise the hole locations on the workplanes (all four of them in this case) and then re-extrude the parts.

With this in mind, I have transferred all the geometry to Sketchup by way of drawing them again (I dread having to do this for a locomotive...), and I've made further progress by constructing a prototype for the Print Bed:

I say prototype because I seem to have blocked off the bed to the projector o.O

That's the spot!  Now we can make out which bits are Plywood, which are Acrylic and which are 3D Printed.  I know I ought to have taken the projector into account seeing as it is the most vital part of the machine, but that's okay because it's an iterative process, CAD; furthermore, it is far easier to amend a model than a drawing, which I should know given how small I like to make my concept drawings.

Until next time...

SLA 3D Printer Project Log 6: Quick Snippet

Since the last post, I have been giving thought to my projector mount - long story short, I believe it will be too flimsy with all that weight resting on an 8mm thread (wrt the vertical adjustment).  As a small update while I figure out what to do from here, I have some basic drawings to clue you in on some ideas for two of the Sub-Assemblies:

I don't draw so well...  I'm not the best calligrapher either...

I have now opted for a tighter design utilizing 3D Printed clamps on the 8mm Steel Rods; I can now drastically reduce the distance, and hence the moment arm the projector will enact upon the structure, enabling a smaller frame overall.

Never one for freehand...

This is an initial design for my Build Platform, consisting of a suspended steel grate (a fine pattern to help grip the print) suspended from four LM8UU linear bearings to stabilise the platform, taking moment stresses off of the 8mm threaded rod, which in turn positions the platform.  I have literally just thought of using two motors like the Reprap as long as I can overcome synchronicity issues.

Another thing of note is that I managed to make the Resin Basin in around 30 mins in Creo:

...Which is why I'm a CAD man ;)

So, not a complicated job, simply laser cut from 12mm cast acrylic to allow the use of heavy duty cleaning agents (Extruded Acrylic has microscopic stress marks which the agents can penetrate and cause further damage); the holes in the end and the bottom (not the flanges, I'll cover them later) are sized to take G 1/4" threads commonly used in PC Water Cooling equipment, the one in the bottom drains the tank of all fluids while the side holes act as fill levels for the Salt Water and the Resin on top - Procedure for filling is as follows:

1. Close the Bottom Valve.
2. Open the Lower Side Valve (the Upper Side Port will have no valve).
3. Fill the tank with Salt Water until it flows out the Lower Side Port.
4. Close the Lower Side Valve.
5. Fill with resin until it flows out of the Upper Side Port.

A similar procedure is done for draining:

1. Remove any Prints.
2. Open the Lower Side Valve.
3. Let The remaining Resin drain out.
4. Open the Bottom Valve.
5. Let the Salt Water drain out.

All fill leveling is therefore done by the tank if the correct procedure is followed, I have it calibrated for 20mm of Resin on top of 110mm of Salt Water, giving 120mm of Z axis Build Area alongside a proposed upgrade of 192mm x 108mm build area once I source a 1080p native projector (once I've sifted through all them "1080p" projectors with an embarrassing native resolution of 800 x 600 >:(  ) .

The other holes on the flanges are simply mounting holes to suit M10 bolts, and another idea as of present is to make a calibration sheet from more 12mm Acrylic set to the same height as the resin to position the projector accurately.  I propose using L plates for accurate positioning of the basin.

Take care :)