How to build a T3 - Part 5
The motion is complete, so we can be sure we've got the hard bit behind us. Now for the fun bit, where our model really starts to look like a locomotive: the superstructure.
NOTE: For this section, you will need to use the Cylinder Tool in the stock editor a good deal. You can find more information about the various input parameters in the User Guide. A few extra things to watch out for:
- Unless otherwise stated, assume that parts should be single-sided: use the "$" check-box.
- Start with a small number of segments, add more if the polygonality is too obvious. If a structure consists of a stacked series of cylinders and cones, use the same number of segments all the way along, to avoid unsightly gaps.
- It's often easier to use Reverse Panels to get a group of cylinder panels facing the right way than work out in which order to put the two reference points in the cylinder tool.
- Look at the parts you have made carefully in the D3D preview, checking for any gaps - these are usually due to cumulative rounding errors, and can easily be fixed by hand.
- Rounding errors are a particular problem with anything that crosses the axis. If the structure is not as symmetrical as it's meant to be, you may get better results if you delete one half and use a Reflect translation on the other.
Step 10: The Boiler
Up to now, we've just represented the boiler as a simple cylinder. One of the most characteristic features of the T3 is the triangular base of the smokebox. This, with the tapered chimney, will announce to the viewer that it is a T3 they're looking at, so it's important to get it right.
[NB: If you're using Windows 98, you may have run into problems with the filesize limit in the editor. In this case, you could consider making the boiler as a component in a separate file.]
Either delete the mock-up boiler, or shift it out of the way, and make a new cylinder with the same settings (see the mock-up page) but only running from L=116 to 183.
From the front view of the drawings, we can see that the lower side of the smokebox descends at a tangent to the curve from roughly ten and two o'clock: W=59, H=211, to the footplate at W=95, H=118. Look at the cylinder panels. The nearest point to 59/L/211 is 56/L/206. To make the tangents, all we have to do is alter the next point down, 59/L/185, to 95/L/118, and discard all the other panels below this one.
Now we just need to change a couple of points from 0/116/186 to 0/116/118 to fill the gap in the smokebox front down to the footplate, and then copy the two lower panels of the front to L=183 and reverse them to make the back of the smokebox. That was easy!
The smokebox door is concentric with the boiler. It has an outer section with a radius of 52cm, and an inner domed section with a radius of 40. We need three iterations of the cylinder tool, each time only tick the cylinder, not the ends:
-
The door rim: L =113 to 116, R=52 and 52;
- The flat part: L=113 to 100, R= 52 and 40 - after making this, do a 0% Stretch L about L=113;
- The domed bit: L=113 to 107, R=40 and 0.
Later we will add hinges and a door fastening.
On most photographs of T3's, the boiler bands are clearly visible, contrasting with the black of the boiler itself. They probably aren't thick enough to justify the cost of modelling them in relief, but they do need to be distinguished in colour. Thus we will break the main part of the boiler into four sections separated by bands. Make a cylinder from 183 to 189 in a light colour, and one from 189 to 252 in a darker colour, then just keep shifting them along to get the alternating bands and boiler.
Suddenly it's starting to look like a T3! That completes the basic boiler structure. We won't have to model the firebox, as it's concealed by the cab and bunkers.
Step 11: Boiler Fittings
Starting again at the front, the first thing to deal with is the chimney. Again, this is a job for the cylinder tool. The chimney centre line is at L=148. We can model it with two conical sections separated by a short cylindrical transition region. As we're not using real smoke, we don't need to make a hole in the top of the smokebox! As the chimney is quite narrow, six segments are probably enough for the cylinders.
| H | R |
| 241 | 27 |
| 272,284 | 15 |
| 422 | 23 |
Beyond the chimney is the dome. Domes were not fitted to the earlier series of T3's, so at a later stage we might want to take this out as a component, to allow us to do two different versions.
The dome is a cylinder of R=42, straight-sided up to H=314, with a slight taper on the top. Again, we can do this with three sections (a cylinder, a cone, and a disc). The c/l is at L=312.
The sanding dome is just a square box sitting on top of the boiler.
There's a lot of fine detail that could be added, but we have the most important bits of the boiler completed, so we might as well move on to the cab.
Download the model at this stage
Next: The cab and bunkers