Thinking outside the box in 3 Dimensions to get a 3D Print to Print

So, my current waiting game with Shapeways and my efforts to make them print things the way I want on their print bed so that it fits appears to be working.  I spoke about this a couple of weeks ago here where I looked at the issue of a standard 80’+ long modern passenger coach being too long for their printer in HO scale.

Traditionally, 3D designers have had to resort to adding sprues to models to force Shapeways to orient their model on the printer the way they want to get it within the size limits of the machine, or to attempt to control which surfaces have the best finish.  Shapeways changed their pricing on FUD earlier this year to more clearly identify what you are being charged for.  One of the changes is a clear separate charge for print material, support material, and machine space.  The result of these, is that adding sprues or more material to force an orientation would potentially drastically increase the price of the part to force (and the part isn’t cheap to begin with at around $100USD without any markup for me if I want to sell it down the road).   If I was going to get the car to print, I was either going to have to split it into multiple parts (with the alignment and appearance problems that can bring), or find another way to get it to print.

I don’t know how others work in their design drawings, but I work using the X and Y axis as my length and width for a car.  The X axis is the “front” if you look at an elevation, and Y as the depth.  The Z axis is the height of whatever I am drawing.  In this case, for a passenger car, the X is is the long side of the car (i.e. where windows etc are.  I set my base point on the X with one end of the car at zero and measure out from there.  For the Y depth, I do a 50/50 split, the zero Y axis is the centreline of the car, over the centre of the tracks.  This lets me mirror the sides of the car once one side is done.  I draw with half the width is in positive Y, and the half in negative Y.  This is important as being a bit rigid helps me visualize what I am drawing, and makes measurements easy as you are working along with the linear axis in the software from zero.

So, back to the issue at hand of parts being too big for Shapeways.  The rendering below shows two rectangles, one in grey is the Shapeways FUD printer maximum print bed X and Y (my models have no issue with being too tall, just too long).  Designing as I describe above, when I scale the car down from 1:1 to 1:87, it is too long and hangs off the end of the printer bed.

ShapewaysAnalysis1Passenger car too long when scaled down to be printed by Shapeways, or is it?

So, how to overcome this?  Shapeways system won’t try to re-orient a part in anything less than a 90 degree increment (i.e. they won’t place it at an angle across the print bed).  In thinking about it, I wondered if while they won’t orient a part at an angle, if I did so in the .STL file that gets uploaded for them to print from, if that would work.  When you upload a model, their system runs a bunch of automated checks looking for obvious failures that would prevent printing, and the size so it can calculate a price. Once I was done the model, It was scaled down to HO, and then I took it and rotated the part until it just fit inside the length of the printer as shown below.

ShapewaysAnalysis2Look at me being cheeky (and a little clever), I turned the part inside my 3D software to a jaunty angle so Shapeways system considers it to be within the maximum print size for FUD.

Doing this, allowed the part to pass the automated checks, the most critical of which is the “Bounding Box”, or the automated systems analysis of whether the part would fit within the maximum size the printer can produce.  Having a positive outcome on this, I went ahead and placed the order.  As of when I am writing this post, the body has successfully printed!! I have no idea what turning the part like I have will do to the print quality, or anything else.  For all I know, the turn will create exaggerated stepping on the model instead of it being oriented lengthwise along the bed, but, it has printed, and I can’t learn if I don’t try.  It’s worth one shot to me to see if it works, given how close the car was to fitting as one piece in the normal orientation.

ShapewaysAnalysis3.jpgShapeways Order Status page showing the car has moved from “In-Production” to “Packing”, meaning its done printing, now the long wait on shipping!

So, the question all of you (or at least some of you… someone, anyone???) are asking, is what is this mystery car you’re working on!!  I’m not ready to tell you yet, but I can tell you that if everything goes to plan, and the order from Shapeways arrives in time, I will have the car at the Brampton Model Railroad Show on September 30th and October 1st, 2017.  I know that’s over a month away, but not everything in my Shapeways order has printed yet, the target ship date is August 31, and my past few orders have taken almost 3 weeks to arrive thanks to getting stuck in CBSA purgatory for taxation at the border (seriously, if you’re going to tax it, just get it done, the math to add 13% to the exchanged value plus a $10 service charge isn’t that hard!!). I’ll also hopefully have a post ready to go for the Saturday morning introducing the model for anyone who isn’t in the Toronto area.  I’ll have more details about what I’ll be doing at the show and the show closer to the dates in September.

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