We shall build a steam locomotive ...

[mrennie]

Now, the image we're using has the loco facing towards the left. When we paint it onto our SideElevationLinedrawing cube, it needs to be facing towards the front of the loco model, so we need to paint it onto the left-hand side of the cube (that is, the side you see when looking at it from the left-hand side of our scene).

Go to the left-hand view:

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Select the Material Panel:

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then Primary Texture:

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and Select Texture:

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and our reference picture:

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[mrennie]

Before pasting the image onto the cube, it's a good idea to boost the clarity by going to the General tab of the Material Palette and increasing the Ambient to about 60ish:

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Go to the paint tool (on the right-hand side of the screen):

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Place the brush over the (left) face of the cube and paint it:

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The image has the correct relative dimensions, but now we have to give it the correct absolute size, and align it vertically with the rail height guide. There's more than one way to do this, but I'll show you a very accurate and fairly easy way.

First, and after locking the x,y,x axis (to avoid inadvertently shifting anything), use the Point/Edge/Face Selection tool to select the top and bottom edges of the painted face of SideElevationLineDrawing. Remember, one way to select several things at a time is to select the first (it turns from blue to yellow), then hold down Ctrl while selecting more.

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Go to the Shape Operation Panel, select Divide

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and at the bottom, in Parameters Divisions, put 3.

[mrennie]

If you're unlucky like me, 3DC will now have hung. Never mind, you get used to it after a few months

Just kill the process (or wait for it to die a slow death) and start 3DC again, choosing to recover the document. Then save it with the next number up, as usual (you get used to this too).

[mrennie]

Change the view so that we are looking from the right-hand side of the scene.

Go the Point/Edge/Face Selection tool (which from here on I'll call PEFS to save on typing!), move the cursor over the unpainted right-hand face of SideElevationLineDrawing until it highlights in blue the points we created by dividing its top and bottom edges. Use Ctrl to select two points that are vertically aligned. Remember (I'll say this again and again to emphasize the importance of it), don't select anything without first locking the x,y,z axis, to stop any shifting from happening by mistake. With those two points selected, create a new edge. Do the same with the other two points.

To be able to see the edges you just created, select SideElevationLineDrawing in the hierarchy panel, get the RMB drop down menu and select Draw > Solid Outline.

Now for a slightly tricky bit. Select the SideElevationLineDrawing object. Then select Copy:

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Click on an empty space in the scene, so that nothing is selected (nothing is highlighted in bold in the scene hierarchy on the right of the screen).

Then click on paste.

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If you did this correctly, you should now have two SideElevationLineDrawing objects, in separate groups, at exactly the same position in the scene.

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Select the new one, go to top-down view, and with only the x-axis unlocked, drag it a bit further over to the right so that it isn't superimposed with the original one.

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Go back again to the view looking from the left-hand side. Select the original SideElevationLineDrawing object and draw it as a wireframe. It should now look as if you can see our two new vertical lines superimposed on the loco image behind it.

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the next step is to align those vertical lines with measurement reference lines on the drawing .... see next post!

[mrennie]

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In one of the smaller viewing panels, select top-down view.

Then select two of the new points that are vertically aligned in the original SideElevationLineDrawing. You can do this by selecting one point and then using the Rectangle Selection Tool (RST) to select both it and the point vertically below it:

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In the main view (looking from the left), you'll see the two points highlighted in yellow.

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Unlock the z axis.

In the main view, drag the two highlighted points until the line that connects them is superimposed on the leftmost measurement line in the drawing:

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Do the same with the other two points, to place the line over the one in the drawing that shows the end of the cab:

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Lock x,y,z again!

[mrennie]

in the top down view, select the upper (nearer to the front of the loco, that is) of the new points we created earlier:

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Go to Shape Operation Panel > Set Point Position (SPP):

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(Note: To make accurate models, SPP is absolutely your best friend, I use it a lot!!)

Click on it and make a note of the z coordinate of this point. Then click Cancel.

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Z = 3.9048 (yours will be different)

Do the same with one of the points on the other side (the cab end).

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Z = -3.3251

Now calculate the difference (distance along the z axis) between the two points. In my case it is 3.9048+3.3251=7.2299 (that's 7.2299 feet). Yours should be something similar.

In the diagram, the distance is 5'6" + 8'1" + 5'9" + 6'3" + 7'10".

Convert the inches to decimal fractions of feet: 5.5' + 8.0833' + 5.75' + 6.25' + 7.8333'.

Adding it up: 33.4166'

That means that we have to scale up our SideElevationLinedrawing by 33.4166/7.2299, which is equal to 4.622.

[mrennie]

With our original SideElevationLineDrawing (the one in wireframe mode) still selected, click on Shape Operation Panel > Scale Selection. In the Parameters > Type, leave it on "Scale" and put 4.622 into the Z and Y.

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You can now delete the copy of SideElevationLineDrawing, and draw the first one as a Solid Line Drawing.

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Unlock only the x axis.

In the topdown view, drag SideElevationLineDrawing until it is a bit further to the right of the scene than RailHeightGuide.

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Unlock the y axis only.

In the left-hand view, select SideElevationLineDrawing and drag it upwards along the y axis until the line that marks the rails is aligned with the top edge of our own RailHeightGuide object. You might want to stretch RailHeightGuide along the z axis first, like I've done just now:

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One last thing before we've finished this step. it's really important to be accurate. If you look at the above screenshot, you'll see that the line drawing is inclined ever so slightly. We have to fix that, or it'll bug us later on. So, select SideElevationLineDrawing and then the Shift Selection button:

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Then experiment with small values in the Rotate X parameter until the rail guide line in the drawing is aligned with our RailHeightGuide. I found that -0.3 did it.
Finally, drag SideElevationLineDrawing down a little bit to get that rail guide aligned perfectly.

Important note: The top of the rail is aligned with the edge of the tires of its wheels, not the flanges, which go lower than the rail tops (obviously).

[mrennie]

Lock the SideElevationDrawing object and drag it into the ModelGuides group in the hierarchy.

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Now we come back to those objects 1_2000_bo01 and 1_2000_bo02 (remember them?).

1_2000_bo01 belongs to the pilot truck. With only the z axis unlocked, in the left side view, drag it until it is aligned with the centerline of the pilot truck in the diagram. Once there, unlock only the y axis, and drag 1_2000_bo01 upwards to approximately where the pilot truck pivot should be.

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Do the same with 1_2000_bo02. It should be aligned along the z axis with what would be the pivot point of the loco's rigid frame when going around a curve. In the case of three driving wheels, that's the centre axle (in real life, the main job of the pilot truck is to help to ensure that this is so, to improve "tracking", which is why it's called a pilot). In a 4-8-4, it would be somewhere between the two centre drivers.

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There's just one more guide to make - the one that we use to verify the track gauge. That'll be in the next post.

[mrennie]

Now for the rail guides. Standard gauge track means a distance of 4 ft 8.5 inches (4.7083 ft) between the inside edges of the rails. The width of the rail head isn't so important but we might as well do it properly and set it to about 2.56 inches (0.2133 ft)

In top-down (plan) view, drag a cube into the scene. With it selected, click on Scale Selection, choose Scale To and in the parameters put X=0.1067 (that's half of 0.2133), Y=0.15 and Z=20.0.

In side view (looking from the left), select the side face of our new rail.

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Extrude that face by 0.1067.

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Draw the rail as a wireframe so that when you see it in the plan view, it has a line running all the way down the middle.

In plan view, with only the x axis unlocked, drag the rail sideways until the middle line is exactly aligned with the centres of our two pivot cylinders (and zoom into the view as much as possible to check that it is accurately aligned). Then lock the x axis again.

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Make sure only the rail is selected. Click on the copy button, then click in an empty space in the scene so that nothing is selected, and then click on the paste button, so that we have two rails in exactly the same place, each in its own group.

To get the rails into the correct position, with 4.7083ft between their inside edges, we need to move one of them to the left by (4.7083/2)+0.1067 ft, and the other one to the right by that same amount.

Select the first rail, click on Shift Selection and enter -2.4609 into the Shift X field.

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Select the second rail, click on Shift Selection and enter 2.4609 into Shift X.

Now, for convenience, merge the two rails into a single object: select one of them, then holding down CTRL, select the other, so that you have them both selected. Then click on the Shape Merge button (on the right).

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Rename the merged cube as Rails.

EDIT (26 March 13): In the original post, I said to shift the rails by 4.7083+0.1067, wherease it ought to have been by (4.7083/2)+0.1067 ft. I've corrected it in bold.

[mrennie]

We already made an object called RailHeightGuide but our new Rails makes that one redundant! In side view, drag Rails in the y axis until its top edge coincides with the top edge of RailHeightGuide. Then delete RailHeightGuide and drag Rails into the ModelGuides group in the hierarchy. Scale it up along the z axis by a factor of 2.0 (so that it's longer than the loco).

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[mrennie]

Have a look at the scene in the "looking from the front of the loco" view and if DO NOT DELETE ME is too close the rails, drag it further over the right, where it won't get in the way of our loco model. Then lock it.

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[mrennie]

Now to make some wheels.

First make sure that all the members of the ModelGuides group are locked!

Drag a cylinder into the scene, making sure it is put into the default position (in a group of its own at the top of the hierarchy, not into a group inside another group).

Select the cylinder and in Longitude, put 64. That's so that we get a smooth wheel.

Select the cylinder, select Shift Selection and put 90.0 into Rotate Z.

Draw the cylinder translucent, so that you can see its group centre.

With the y and z axis unlocked, place the cylinder so that its centre is aligned with the centre of the rear driving wheel in the background picture. For now, it's not necessary to be extremely accurate (we'll place it accurately later on).

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Click on Scale Selection, choose Scale and experiment a bit with putting the same value into Y and Z until the cylinder is the same diameter as the wheel boss end of the crankpin. I found that 1.45 was about right.

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Look at the scene from the front and use the PEFS and RST to select all the faces around the circumference of the cylinder.

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Without deselecting them (easily done by accident), switch again to the side view. Use Extrude Selection to extrude those faces, making sure Extrude As Region and Extrude Using Face Direction are ticked. In Extrusion, put 0.08. Leave Bevel Amount as 0.0. Draw the cylinder as a Solid Outline.

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[mrennie]

Rename the cylinder as Driver (just so we don't forget what it is!).

Now to make the outer part of the wheel. First of all, still with the faces around the circumference selected, copy and paste our Driver object, again making sure it ends up in its own top-level group and at the exact same position as Driver. It will copy only the faces we have selected, not the entire object.

Select the second Driver object and scale it (use the Scale Selection button and choose Scale) by 2.35 in the Z and Y directions.

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For convenience, rename this second cylinder as Driver2.

Copy and paste Driver2 so that we have another one at exactly the same place. Rename it Driver3.

Hide Driver and Driver2. This is because we need to do some things with Driver3 and it's easier if the other two cylinders are hidden.

Select all the faces of Driver3 (that is, all the faces around the circumference) and extrude them by 0.2. Then extrude them again by 0.26.

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Unhide Driver2, select it and click on the Invert Selection button (in the Construction panel).

Select Driver2, hold down CTRL and select Driver3, then click on Shape Merge. Driver3 is "deleted" by becoming part of Driver2. Now, it might look as if Driver2 is a solid object, but it's deceiving. We have to do one more thing to make it a single solid object - select it and click on Optimize Shape Geometry in the Construction panel, without changing the values of the Parameters. What that does is to merge overlapping points into a single point. I use this a lot! It helps enormously to avoid those horrible flickering pixels you see in some models (caused by very tiny cracks in the joins between faces and edges).

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Select the faces as shown in the next picture (do this by selecting one face, then hold down CTRL as you drag the mouse, holding the LMB, around the other faces):

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Extrude this faces by 0.03.

Use the Flip Shape button in the Construction panel to flip Driver2 about the X axis (so that we're looking at the inside face, or back, of the wheel). We need to tidy up a bit before adding the flanges. merge the inner and outer faces of each segment. I do it by selecting the two faces and the applying Merge Faces from the Plug-Ins menu (or F6). Like this (until they're all done):

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This still leaves some useless points along the edges. Once you've merged the faces, select those useless points and delete them.

[mrennie]

Useless points selected:

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Select all the horizontal edges (lines) around the circumference, but just the wide ones, like I show here:

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Click on the Divide Selection button to split all those edges into two (at this point, my 3DC hangs and I have to restart it and recover the model ... ho-hum).

By the way, while doing all this, it might be a good idea to hide all the objects in ModelGuides, because while we're doing the wheel, they can sometimes obstruct the view.

Select all our newly created points around the wheel.

Click on the Create Edge From Selection button to join up all those points into a new edge all around the circumference of the wheel.

Select the rearward faces that we've created:

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Extrude them by 0.1.

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Tidy up (merge) those back faces in the same way as before.

Flip Driver2 about the x axis again.

See how the thing we did to make the raised part of the tire has left us with some more tidying to do:

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We'll do that too before carrying on.

[mrennie]

Tires are actually tapered so that they sit at an angle on the rail head.

Select all the outer points of the tire edge, around the circumference,

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but making sure to select the last one while in side view.

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Click on Scale Selection, choose Scale, and put 0.99 into Y and Z.

Change to the "looking from the rear of the loco" view. Unlock the x axis. Unhide Driver. Put Driver2 into the same group as Driver (so that we can more easily and safely move them together). Slide the two objects (now you only need to select one and drag it ... all the others objects in the same group will move with it) until the wheel is aligned with the outer edge of the rail head like this:

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Select the middle points, like this:

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and slide them along the x axis until they are just slightly away from the rail head's inner edge:

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