Back to Business: Snowplows Again

The Dunsel Line shops are predominantly (literally) a virtual operation at this point. Naturally, most work done there is done on the computer.

I’ve decided to take a brief break from designing the Form 5 coupler and go back to an earlier project: the Q scale (1:45) snowplows for the 3200s. Previously I had stated that I would produce the snowplow “blades” from cardstock and glue them to the 3D printed frames I’d produced. I’ve decided to scratch that idea and just have the whole thing printed as a complete piece. This opens up the product for anyone else who would desire to reequip their MTH 3200s and/or 2-rail them.

On Sunday I went back in and added the blades and accompanying parts.

I think they look pretty good. And, better yet, they pass the tests for Frosted Ultra Detail. They’re ready to print!

Not so fast. Wait a minute… Where are the nuts holding the blade to the frame? They’re in my 3D model and they’re of a size that’s printable in FUD.

This is Shapeways' preview image. As you can see, the nuts pictured in the 3D model are not present here.

This is really starting to piss me off. This is the third time parts have gone missing when I've uploaded a model to Shapeways. (I am not blaming Shapeways for this error.) Somewhere in the conversion from the .skp file to .dae (done in Windows via "File" > "Export" > "3D model...") parts go missing and I still can't figure out why.

I'll delay printing until I solve this constant issue.

But in other, non-virtual, news I've begun fabrication of the car floors for the 3200s. I'm using 0.060" Evergreen styrene.

The holes drilled in the floor mark where the trucks will be mounted. If you have a sharp eye you've noticed that one of the holes doesn't line up with the line drawn down the length of the car body. This is not an error. The hole is correct, the line is off on that end by about 1/16". Since I won't be reusing the trucks the cars came with, I'll have to build my own and I'll be purchasing a set of wheels from NorthWest Short Line soon.

The 3200s are equipped with 28 inch wheels. In 1:45 scale, this comes out to a diameter of 0.622 real inches. 30 inches in O scale comes out to 0.625 real inches. The 30 inch wheels will therefore be 0.003 inches too wide, but I'm willing to settle. Once I get the wheels, I'll acquire a pair of cheap trucks for the floors to sit on while work progresses.

Erroneous Values!

So, after pulling my hair out trying to find this separate piece, I gave up and decided to reduce the thickness of the "finished floor" by 1mm just to see how much money this would knock off the total price. It turns out 1mm translates out to about an $18 savings. More importantly, though, the product no longer registered as having "thin walls" or multiple parts! The loose piece didn't exist (thank goodness) and, as designed, all of the walls were reading as having acceptable dimensions. The problem was just some mathematical artifact in the file's coding picked up from somewhere. The new, thinner, file didn't have such errors. Success!

But wait. Not so fast. I knocked off a few more millimeters here and there (things I decided weren't essential and probably wouldn't actually help much) just to see how much more I could get the price to drop, uploaded the new file to Shapeways, and suddenly two of my old friends reappeared. Now knowing what to look for, I was able to find them much more quickly. For some reason, part of one of the seats was not registering and this was causing the stanchion connected to that seat to be attached to nothing. (This is where the multiple parts issue came from.) The other problem, it turns out, is being caused by a shape emanating from one of the windbreaks. This shape is too thin for the printing constraints.

Here's the kicker: none of these issues are representative of the 3D model I've created. I can't just fix them on my end, because they're non-existent. This means that there's either an error in the exporting process from Google Sketchup's native file format (.skp) to Collada (.dae) which is one of the acceptable file types for Shapeways, or the problem is with Shapeways and they way their computers are reading such files.

Either way, I have no solution at present.