Monday, 1 September 2014

28mm terrain buildings in FreeCAD

Having spent a few hours getting familiar with FreeCAD, we decided to create something actually useful: some exploded diagrams of how to construct our 28mm wild west buildings. Having taken out the mistakes we found during assembly, we just need to finalise the designs - add in a few more tabs, to make construction just that little bit more intuitive - and we can create 3D models of all our buildings.

Starting with the simplest (and before we added in extra locating tabs, d'oh) we managed to put together a reasonable 3D model of our "bank" building

A few components got accidentally deleted, as we battled with ungrouping "compound parts" (simply delete the overarching compound and the component parts become individual again) but the end result was quite impressive, for our first real venture into creating 3D models (rather than just re-positioning models created by someone else).

So now we just need to decide where to add in the extra locating tabs, and we're ready to produce some step-by-step assembly guides - complete with 3D exploded diagrams!

FreeCAD for assembling 3d laser cut shapes designed in 2d in Inkscape

During the construction of our cnc frame (for a pick-n-place machine) we had a number of revelations. The first being that we're actually not that great at realising 2D drawn designs in 3D!
All too often, we'd line parts up and realise they were out by about 3mm - usually the thickness of a piece of mdf, where we'd forgotten to allow for abutting edges or to compensate where one piece meets another.

Rather than go to the trouble of cutting and assembling (and later, trying to fudge, fix, and eventually throw away) pieces, only for them to end up in the bin, it'd be far easier - in the long run - to assemble everything virtually, on the screen.

Steve does this a lot, using 3DS Max. We looked at that a few years ago, but it has far too many buttons for us! What we needed was something simple to use. Google Sketchup is great for layout out shapes into a 3d design - we'd already done this quite a bit with our spaceship terrain a few months back - but it doesn't have the ability to import and extrude your own CAD drawings; everything has to be created from scratch in Ketchup, which is a bit of a chore.

You can import your own drawings in Sketchup, but it requires a Pro licence - costing about £500. So we need something simple, and cheap, to create our 3D master pieces.

OpenSCAD is a popular 3D package used by a lot of nerds and geeks and is great for creating shapes using a programmatic approach, for boolean operations, additions and subtractions and the like. It can import flat svg files and extrude them, to create 3D models from 2D cad files. The only issue with this is programmatically placing each shape gets complicated, very quickly!

So we need something easy, cheap, able to import svg (or other vector formats) and with a simple interface for moving the pieces around.

Luckily FreeCAD ticks all the boxes! Of course, like starting out with all new applications, the interface takes a bit of getting used to, but it's actually really easy to turn a 2D CAD drawing into a 3D representation of the project. To start off, simply import the SVG of the CAD drawing

Now, make sure the drop down menu is set to "Parts" (for parts editing). Without doing this, half of the toolbars either disappear, or are greyed out. With all of the CAD drawing selected, hit the "extrude" button (a box with an up-arrow against it) and enter the height 3mm. The CAD drawing will magically become a 3D image!

Even if the CAD drawing has "removed parts" from planes (e.g. a drill hole cut into a rectangle) these don't come through in FreeCAD. The shapes exist, but they need to be removed, using a boolean operator. Luckily this is easy enough. Select the part you want to keep, then - holding down the control key (not shift, as is common in most applications for selecting two or more parts) - select the part to be removed

Hit the boolean subtract button, and the selected piece is cut out of the main shape. It's a simple enough job, just a little time-consuming if you've got loads of tabs and slots to cut out.

With all the slots and tabs cut out, we're ready to start assembling. Having only Sketchup as a comparison, in which we had to install an edge-align tool as it doesn't have one as standard, we've no idea if how FreeCAD works is typical, but it's certainly intuitive enough to get going really quickly.

Start off by selecting a piece - the first piece selected will remain in place. Then, with the control key held, select a second piece. The second piece will be moved to join the first, stationary piece. With both pieces selected, use the Edit -> Alignment menu option

There is no toolbar for this, nor is it available in a pop-up menu, so you must use the Edit menu. This opens the alignment screen(s).

Now it's a case of stretching your head around which parts will be touching, once the second piece has been moving into its final position (strangely, the second/moveable piece appears on the left of split screen).
In this case, we want our end piece to stand up at 90 degrees to the base. Rather than mess about rotating pieces, you simply select enough points to allow the application to work out the required rotation.

In the example above, we've selected two points, which will line up the tabs on the vertical piece, with the slots in the base. But we need to provide at least one more point, to align the bottom edge of the vertical piece with the bottom edge of the base.

You can align faces, edges or vertices (corners). By selecting a vertex, you're often actually aligning two edges at once, so we tend to stick with vertices where possible - though sometimes it's handy to be able to say "this edge should run along this edge" or "this face should be touching this face" to help get the rotation correct.

After successfully aligning a few pieces, our 3D design is starting to take shape

And finally, we get to the whole point of learning how to use a completely new CAD package, and the reason behind spending hours longer in the design process - it's cock-ups like the one below we're looking to eliminate by assembling everything on screen before sending our designs to the laser cutter

We've done the classic trick of offsetting our tabs by 3mm (the thickness of the mdf) and forgetting to adjust it in other parts of the drawing. This actual mistake cost us two sheets of mdf. Not much in terms of materials costs (it would have been a lot more if we were using acrylic!) but a lot in terms of time and effort (especially since we wasted about half an hour trying to bodge/fix it, instead of just cutting a fresh piece!).

3D CAD is a great way not only to visualise the final project, but also a really useful way of ensuring everything lines up properly before even going anywhere near a laser cutter (or cnc router, if that's what you're using). This is especially useful if you're going to be using slightly more expensive construction materials.

But one of the great things that 3D CAD allows us to produce is a set of assembly instructions. So in the true spirit of sharing designs and ideas, we can now easily share instructions on how to assemble the pieces, with anyone daft enough to download our plans and use them in the first place!

CNC pick and place laser cut frame

A few Thursdays back, we started a second version of our CNC frame, for a semi-automated pick-n-place machine. We'd already started one frame, but decided, in the end, that it didn't really follow the idea of small-scale, desktop manufacturing. It was a beast of a thing - really heavy, cumbersome to carry around, took up loads of room, and had massive stepper motors flying up and down the gantry.

A second version followed, a few weeks back, made from some metal brackets from B&Q and a few sheets of Dibond. It was easy enough to put together, but the overall finish wasn't very impressive. It doesn't matter how smooth your linear rails are, and how much you grease the rods - if the rails aren't perfectly parallel, you're going to get binding somewhere!

Steve pretty much said as much last week - as we were discussing the poor performance of CNC frame V2.0 he suggested that the only way to get a decent CNC frame, ensuring everything was square and parallel, was to CNC cut one. Our desktop CNC is still waiting to be set up, so that was out. But we do have a fully functional laser cutter. That's just a CNC with a laser instead of router isn't it?

It took about 6 hours, to design, cut, fit, re-design, re-cut, refit, scrap-and-start-again and finally produce our laser-cut mdf CNC frame. The first lot of shapes came out quite quckly.

The y-axis was up and running in next to no time.
This is actually the fourth version, strictly speaking - there was an earlier mdf version that we aborted after about two hours, because making space for the steppers and everything else was just getting really difficult.

So in this version, the end piece (where the y-axis rails fit in) extends 33.5mm beyond the base plate. This allows us to put a small nema14 stepper motor under the actual frame (you can just see the pulley attached to it, on the left hand side of the bed).

The uprights are reinforced by gluing two-similar shaped pieces side-by-side. The inner piece has slots for the x-axis cross-member, while on one of the uprights, we made a little box to house another nema14 stepper motor.

The x-axis gantry, ready for fixing over the y-axis travelling bed. At this stage, the gantry is independent of the other part of the CNC. We've yet to decide how to fix the two pieces together. We're even toying with the idea of being able to dismantle the overhead x-axis (by unbolting the "feet" of the gantry from a baseplate) to make storage a little easier.

For the x-axis, a single linear bearing will sit on the one rail with skate bearings fixed on the top and bottom. The skate bearings will run along the back piece, to stop the main bearing from rotating as it travels left-to-right across the gantry.

The final design is just over the size of an A4 sheet of mdf. This means the device will be small enough to be portable, as well as comfortable to use on a desktop, without taking over half of the room, when in operation!

Next time we'll be fitting the x-axis rail and fixing belts to the motors to actually get something moving!

Friday, 29 August 2014

New designs always take a bit of revision

Despite recent successes, it was only a matter of time before we screwed up a design. And, of course, it had to be one of the more adventurous designs that got messed up.

It's only when fitting these miniature buildings together that you realise where the 3mm thickness of the mdf has been left out of the plans. In this case, we had to hack 3mm off the bottom of the front and back panels, in order to get everything to fit together properly. We also seem to be missing a couple of little bits of roof trim. And the roof doesn't quite meet in the middle at the very top (it's off by - you guessed - 3mm).
Although the model actually goes together (with a bit of hacking), compared with our other buildings, it just looks a little, erm, scruffy. Or maybe badly designed. It matches the source photo we were working from, it just doesn't look as nice, on the tabletop, alongside the other buildings.

Our small building was also less than successful. It looked great, right up until the point where we added the ridiculously over-sized canopy. Then it just looked horrid. Maybe a few stickers might have improved things, but we gave up on the canopy idea and knocked it off completely.

Replacing the canopy with a little hanging sign, and it looks much better! What's not immediately obvious is that we actually spent a bit of time making the inside of this one quite nice - complete with roof trusses. The roof lifts off, so the building can be used for "regular" wargaming terrain too, allowing the player to put their playing pieces inside, if necessary.

The windmill was a mixed success. The 0.8mm birch blades looked great when glued into place. We placed them at a slight angle, meaning each one had to be glued individually onto the centre circle. And that's where it got a bit tricky. Because only a tiny edge of the birch is actually in contact with the glue, the blades are very, very delicate.

The photo above shows the windmill after having ten of the twelve blades glued into place. The only problem was, one slight knock, and half of the blades simply fell off! Perhaps a solution might be to laser cut the blades and a centre disk all joined together, and somehow twist the blades to a slight angle (after seeing this, the blades absolutely have to be twisted - they can't just sit flat!)

The only model that went together easily was the water tower. The barrel is made from strips of mdf, wedged together inside a few tight rings - just like a real barrel is made. We really like the effect - but this means we've a dilemma about stickering it up. Bare mdf just looks nasty. But if we wrap a sticker around the barrel, we'll lose the "planked" effect, which looks so good.

When making the barrel body, we lined up all the planks into a strip, and joined them with a strip of sticky tape on the back. This made it easy to simply curl them into a ring, and place inside the barrel hoops. Maybe one answer might be to apply one continuous sticker at this point, and slit along each vertical edge, to allow it to fold around, leaving each plank with it's own individual sticker on the face?

All in all, it was a mixed night of success at BuildBrighton last night. Some of the buildings went together easily, some not so well. But at least we now know where we need to make revisions to the plans. And we did get to drink plenty of tea and talk plenty of nerd. So overall, it was a pretty good result, after all.

Thursday, 28 August 2014

More laser cutting 28mm terrain, wild west buildings

We've decided to have a bit of a push with our wild west terrain (if only so we can get it done and move onto the next massive laser-cutting project, a football stadium, but more on that later!)

We've already got a few "standard" building shapes, which can be mixed-and-matched to create a variety of different buildings. But if we simply repeated our few building designs over and over, we'd end up with a pretty boring looking wild west town! So we've been getting a little bit more adventurous with our designs.

All of our building designs start out like this - a reference photo and lots of overlaid, overlapping parts, drawn to try to give some idea about how they all fit together. Then we produce a "cleaned up" version of the drawing, and send it to the laser cutter:

Given we've had such a miserable "last-bank-holiday-before-Xmas" and the summer seems to have deserted us even before August is out (thanks, Hurricane Bertha) we've spent a bit of time stuck indoors. But it's not all been watching New Tricks and Great British Bake Off. No, we've been busy designing loads of "interesting" looking buildings for our wild west town.

And last night, managed to spend a good few hours at the laser cutter, cranking out kits for our miniature buildings. As yet they're untested, so it's likely that we'll have to amend the final designs. But so far, things aren't looking too bad....

(what's with the half-uploaded files, Google? There are more than just a couple of photos turned out like this in recent weeks)

As well as our standard, 3-inch-wide buildings (tall and short) we found a photo of a tobacconist, squeezed between two larger buildings, so set about creating a super-small building that we could use as a trading post, a telegraph office, tabacconist and so on, by simply changing the top part used to display the signage.

To add a bit of character, we even created a windmill and a water tower for our miniature town.

We've got a jail building on the maker-table too - made entirely from lollipop sticks, to simulate a log cabin (it's hard to create an interesting looking textured surface out of flat, laser-cut planes) so we squeezed some jail bars onto the relatively small windmill section

After cutting out the pieces, we thought that the windmill blades looked far too "chunky" for the model (in truth, the uprights don't look quite right carved out of 3mm mdf, when the design was built for 2mm stock, but it'll do, as a test piece). So we quickly transferred part of the design onto some 0.8mm birch

As we'd run out of "laser-friendly" mdf, we started using some cheap-n-cheerful 3mm mdf from Wickes. Unlike the laser-friendly stuff we got from an online supplier - which has an almost fluffy, untreated surface - the Wickes mdf was really nasty to work with. Both sides are really smooth and shiny, and left a sticky yellow film over everthing - the surface of wood being cut, the cutting bed, the insides of the laser cutter - it got everywhere!

Just before finishing up for the evening, we quickly hacked out a toilet/dunny from a piece of scrap!

With about five "structures" (a few of buildings, a windmill, a water tower and a dunny) bagged up (to keep the different parts separate) we set about cleaning up. The sticky yellow film took quite some removing on its own, so we ended up resorting to some Mr Muscle.

Hopefully this hasn't leaked under the bed. And if it has, let's hope it doesn't do anything drastic like make the belt perish!

After about two and a half hours of lasering almost non-stop, it was time to give the laser cutter a rest and bring our home-made Airfix-a-like model kits home. As each one takes anywhere between 30 minutes and an hour to assemble (including glue drying time) there's probably a full day's work in putting them together. So, softly, softly, over the next few nights, we might actually make some progress....

Tuesday, 26 August 2014

Wild west 28mm terrain water tower and windmill

With the miserable wet Bank Holiday, the wind rushing in off the sea, and the severe weather warnings for the South Coast this weekend, we decided to stay indoors, nice and warm, slurping tea and designing some more buildings for our Wild West town.

Water towers were quite a common feature of towns in the Old West. When the railroads came, they were vital for topping up the steam tanks, and so were generally quite high structures, dominating the skyline, even if they were not the largest of buildings.

Our water barrel is made just like a real barrel, with vertical strips of wood arranged inside some barrel hoops. We're undecided whether or not to put a sticker around the outside of the barrel, or use the natural wood appearance from the laser-cut mdf.

Although water towers (obviously) carried water, some towns also had pumps, to draw water up from the ground. Many of these water pumps were served by windmills.

Not like the european windmills that had massive sails, and loads of torque for moving enormous millstones to grind flour - these windmills were relatively small, but with loads of fans, to easily catch some of the dusty desert winds passing through

Because the weather has been so bad, we've not had chance to get down to the studio and fire up the laser cutter. But the time has been well spent, preparing. So next time we're down there, we'll be able to crank out a few more (slightly amended) buildings, and add a bit of character to our wild west town, with a bit of tabletop eye candy.

Monday, 25 August 2014

More 28mm wild west terrain buildings

Inspired by examples of laser-cut buildings, and given the (relatively) quick results we've had from cutting our own wild west themed buildings, and decorating with stickers (rather than modelling and painting them from scratch) we're going all out to produce a "town" of about eight different styled properties.

Which means, given that it's the bank holiday, more laser-cut goodness!

Our buildings are quite small, compared to some of the "proper" manufacturers out there (like 4Ground or Sarissa) but there's a reason for that: since we're building boards which are 6" x 8" and each playing square is one inch, we're trying to keep our buildings to about three inches across, and only sometimes going as large as four inches across.

This means that a board placed "long-ways" could have two buildings along it's long edge, separated by a single or a double square. Or we could place a 4" wide building in the middle of the short edge, leaving one square either side of the building (or two squares between buildings, if two playing surfaces are placed against each other, and a 4" wide building placed in the centre of the short-edge of each).

While not exactly huge, our buildings fit quite nicely with the 28mm scale that most miniatures manufacturers produce. We're not looking to make a massive playing surface - we just want a few buildings to make an otherwise plain-looking playing surface look a bit like a town from the wild west.

With all this in mind, and using various online sources for inspiration, we've managed to design, cut and assemble another western-style building in less than a day. This time, it's a hotel-like building, with a balcony around the second floor.

As ever, all the drawing and layout was done in Inkscape:

Our trusty LS3020 made short work of buzzing through some 3mm mdf (ideally we'd like to make the buildings from 2mm mdf, but we have a stock of 3mm so that's what we're using!)

We've decided to go a stage further this time - although we've no plans to use our buildings for anything other than a showcase game for our generic electronic board gaming system, a few people have already asked about having some of these buildings made up for their own gaming. And if others are likely to want to use these plans, then it seemed sensible to add in some extra little features:

Like a detachable roof, and removable interior floor for the two-storey buildings. It's a bit late for our early single-storey "stores" building (since the roof has been glued on) but we can always retro-fit a removable roof to our "hotel" building (and even add in some supports for a removable second storey floor). For this building, we've planned for them from the start.

When assembled, the lip going around the inside walls will allow us to drop a 3" square floor in through the roof - effectively creating two accessible, interior rooms where players can place their miniatures to indicate that a player is inside the building. It's not something we've coded for in our electronic games, but the if the buildings are used in any other game ruleset, at least we can accommodate this, should anyone need it.

Here's our latest creation (above) alongside the previous buildings, just awaiting some stickers to jazz it up a little. Since this building is in the style of a wild west hotel, we're probably going to have to change the signage on the other building!

Both of the two-storey buildings have been designed with detachable fronts. This will allow us to make a range of different building styles using a basic template for the building construction. It also means that, when used in a tabletop game, getting access to the miniature playing pieces placed around the buildings can be made a little easier, by removing the front canopy of a building.

An unexpected benefit to this approach is also the ability to "mix and match" different building fronts, onto different building styles

We're getting a little impatient to see our wild west building actually appear on the tabletop, so we may yet just cut another of each of our buildings to date, and have a simple, small town of just six or so (very similar looking) establishments.

Sure, laser cut buildings don't have the same detail as scratch-built ones. And stickers will never give the same impressive appearance as a properly built, painted, inked-and-drybrushed piece of terrain. But they are a pretty easy way of building a relatively large playing terrain, quickly. And for that reason, we need to focus on getting our wild west town finished, rather than worry too much about them not being "real hand-built terrain"!