Finally a successful upload!

Alright! Finally, I’ve uploaded a model successfully. I continued to struggle with inverted normals until I figured out how to get Accutrans to fix the remaining normals. The do-it-yourself active worlds page came to my rescue when the Accutrans help files failed to load, and it turns out all you need to do is click on a couple of semaphore flags, then click on the model.

Once that’s done, you just have to save it as a Collada (.dae) file again. Unfortunately, somewhere along the line, the model got expanded a hundred times; it also seems to lose its units. As Shapeways interprets such files as cm, the resulting model was 778 cm long (about 25 feet for those of you who remember those). That’s a bit too big for the Shapeways printers, and a bit too big for HO too.

Fortunately, Accutrans knows all about scaling, and so, all I had to do was to save it at a scale of .0254, and I got a part that ought to work.

As you can see from the screenshot, it’s apparently only going to cost me $10 to print the side, which means that the whole model might come in well below my original $100 estimate.

Finally a Water-Tight Mesh!

Holy cow, this was harder than it should be! Shapeways keeps responding to numerous attempts to upload pieces of my model with an error stating that I have inverted normals. Yes, I understand why that might be a problem, but in a model with some 2000 faces (on one side of the car alone), some of which are extremely small, figuring out which ones are inverted is like looking for a needle in a haystack. In fact, if you look at the model with normals displayed in meshlab, it looks a little bit like a haystack!

It was time for a new free tool. So I downloaded AccuTrans 3D, which, while not free, is only $20 CAD for us Canadians, while the rest of you have to pay $20 USD (thank-you mouse guy from Regina!). We’re still in the virtually free world, but time is getting expensive. I still have inverted normals, but Accutrans enabled me to get a water-tight mesh, which I happen to know was going to be a problem at some time. Tracking down the holes in my mesh turned into the following little dance:

  • Export the model as a 3D model Google Earth (.kmz) file from SketchUp!
  • Rename the .kmz file to .zip and extract the .dae file inside
  • Open this .dae file in MeshLab and save it as .stl
  • Open the .stl in AccuTrans and choose “Tools/Check for Water-tight Meshes”
  • Now, the first hole I found was big enough that I could find it immediately. The others were tiny (but I guess still big enough to let water drip out), and the way to find them was to turn off the VCG layer, so I could see the holes, zoom in and turn on the VCG layer again so I could relate them to the model.

Sides and roof modeled in Sketchup

Well, I’ve learned a ton about Google SketchUp since starting on this project. Today’s lesson was about groups. Now in every other drawing program I’ve ever used, groups were of little actual utility because in order to edit the elements of the group, you had to break the group and recombine the elements. In SketchUp, on the other hand, you can edit the group in place, which is a huge boon when you’re dealing with groups of thousands of elements. For much of the past couple of weeks as I’ve been modeling, I’ve been struggling with SketchUp choosing the wrong element when I’m trying to pick things: it often wants to choose an element behind the one I’m interested in. I can now see that combining elements into groups and editing the group is the way to defeat this annoyance. The more I use it, the more I like this tool.

Anyway, as you can see, I’ve not modeled the ends yet, and there are a many details to go, but the car is starting to take shape.

Starting on a passenger car

Well, you may as well know I’ve started on my next Proto:87 project. It is going to be the passenger car here, which I sadly know little about except that it ran on the Pembroke Southern behind my locomotive. I believe it was a GTR car, about 60 feet long, but the number and all other information seem to be lost in time.

Now for the approach. When I was in Houten, I got a chance to handle some models made with 3d printing by Shapeways. This got me thinking about the best way to make the roof, which, as you can see, does not present any useful flat surfaces to make construction easy. So, I’ve been busy modeling this part in Google Sketchup with a mind to getting it made for me. Then, I thought, well why stop there? So the whole sides, ends and roof are going to get printed. I’m going to do the underframe in wood because it would have been unpainted wood on the prototype.

Exciting times! Here is the quarter roof after I figured out how to do the compound curve. I spent a number of evenings figuring out Google Sketchup before finally getting this together. The trick turned out (for me) to be to draw longitudinal contour lines in AutoCad. Then I transferred this drawing to Sketchup and moved the lines so they lined up with their locations on the transverse section (that’s what the ticks are on the far edge). There is a whole lot of work involved in stitching the adjacent lines together to form a surface, and I guess I could then go and smooth all the lines. I’m happy enough with the triangles; they should be small enough and even enough to be hard to discern in the finished product.

The caboose is finished!

Finally, I finished the caboose. It was down to the wire to finish it before the big train show this weekend, but here you have it. Overally, I’m pretty happy with it.

Next up? Well, I’ve got a couple of non-P87 models under way, and I reckon I’d better finish them. Then, I’m hoping to start the big basement reno sometime this winter, which will pave the way for (drum roll please) the layout!

Stay tuned.

Caboose roof

Here you go, the roof is just about finished; there’s a little weathering to do, and perhaps a little patina on the smoke jack.

I thought for a long time about the covering. I think this was likely canvas, although I don’t have any proof. Once I’d decided it was canvas, I spent weeks looking for real evidence as to what a well-maintained canvas roof should look like. I’ve seen loads of models with tissue paper on the roof to represent canvas texture, as well as seams between sheets. I found a number of references and pictures on the web to restoration efforts involving canvas roofs, and found that these were universally made in one big piece of canvas. Once the canvas was stretched over the roof, it was then painted. So, are the seams on other models bogus? If you paint canvas, I wouldn’t expect much texture to remain, especially in HO scale.

The boards leading from the ladder to the running board are another supposition. If the roof was indeed canvas, they would have wanted to protect it from brakemen’s feet. However, in the good side view we have, I can’t see any evidence of a normal platform here.

The running boards are plastic, of course. You don’t paint running boards because it makes them slick. So, they are finished in my recipe for well-maintained wood: Humbrol matt 63 (sand colour) base coat followed by some dry-brushed matt 170 (dark brown) then some dry-brushed light grey, and finally a wash of dark grey. Like the underframe, I may start doing these in wood.

When the inevitable aerial photograph shows up shortly after the model is completed, I’ll probably wind up redoing much of the roof. But here it is for now.

Next step: I need to cut the bottom out of the cupola now that it’s glued down, and create an interior for the cupola at least. I hadn’t planned to make an interior for this model, but there are so many windows in the cupola, I don’t think I can get away with that.

Lettering still wet

I just finished doing the lettering. This is a dry transfer, which I had made by All-Out Graphics here in North Vancouver. The artwork was my own, of course. It’s not cheap for the short runs that I need, but I much prefer working with dry transfers, and they do a nice job.

We’re definitely down to the short stokes now! I cut a new weight this evening, and I expect I’ll install that along with the doors tomorrow. I’ll get my son to mix the epoxy for the weight — gotta get them hooked early.

Caboose steps

I hemmed and hawed for a while before finally getting down to making the steps. My initial thought was I would etch the steps as one of my origami etchings. Then, when the etchings didn’t work out, I figured it might be easiest to bend the two stringers from a single length of brass strip.

Finally, I settled on a more typical approach. After bending up the stringers on a simple jig, I placed them in two holes the correct distance apart. I soldered the top step on first flat against the block into which the two holes had been drilled. Then, I put the other ends of the stringers in the block and soldered the bottom step on, soldering them perpendicular to the block.

After all that pondering, it turned out to be a good deal easier to solder the steps up precisely. They wound up taking only about a few minutes each, and so, I made an extra.

To install, I had the most success when I blu-tacked a spacer strip to the side sill, and then held the steps against the spacer. The stringers are glued to the back of the sills, and I’m still pondering whether I should reinforce them with some sort of pinning.

Conversion Chart

You’d think by now that I had every piece of brass and plastic available. However, for whatever reason, I’ve been holding off and only buying strip brass piecemeal for all these years. This Christmas I finally broke the bank and spent the dough required to get kitted out with at least one of each of Special Shapes’ and KMS’ strips. I’ve got a new way to organize these sorts of things, which involves some recycled cardboard and a Famous Grouse box, and so, I spent a little time putting the strips away.

Along the way, I wound up making another conversion chart for fractions to decimals. I used to have one of these hanging over the workbench, but it’s gone now. They’re a very handy device, and cheap too. So, if you have a printer, you’re welcome to grab this one and hang it over your workbench too. I hope it helps you get faster. I created it on Google docs for easy sharing

Brakes mostly done

Here are the brakes almost completed. This is, I think the first time I’ve used turnbuckles to model the clevises. These are tricky, and I think I’ve decided the best thing to do is to glue them to the rods while they are still on the sprue, then cut them in half. You’d wind up sacrificing half the turnbuckles, but I think I lost that many to the dust bunnies anyway.