LMS Fowler 2-6-4t Chassis Construction
Before starting the production process a vast amount of reference images were gathered from various sources across the web. This was done due to the fact that the only image of the actual train model acquired from the museum is from one angle and is also obscured by a reflection on the glass viewing case. Consequently additional points of reference were required to view the different aspects of the train from different angles. Although a large number of images were gathered only several of these are exactly the correct steam engine, many of them are of a BR standard 2-6-4t which is a very similar train based on the LMS Fowler. Perhaps the main reason for a lack of photographic material of the LMS Fowler 2-6-4t is due to the fact that none of the original models survived or have been restored, as a result some of the images collected were taken during its years of service and consequently the quality of these are rather lacking.
The task assigned preceding the first group meeting was to construct the chassis for the steam engine with its basic components included for animation testing next week. Based on the collated reference images a side profile of the steam engine was chosen as a starting point, which was imported onto a plane in the left viewport of 3DS Max. From this image the rough layout of the steam engine could be mocked up based on the real dimensions found at http://en.wikipedia.org/wiki/LMS_Fowler_2-6-4T. This process allowed the rough size of each element to moved into position by aligning each object with left side image to gain an approximate representation of its layout.
Wheelbase Layout Test
The next step was to produce the shape of the main chassis, which was achieved by starting with a box object, this was given numerous additional edges allowing it to be manipulated by moving the newly created vertices. The rough outline shape of the front part of the chassis was produced first following the contours of the side image whilst toggling the object's opacity using Alt + X on the keyboard.
Basic Chassis Creation
Having made the basic chassis for the front part of the steam engine further detail was added starting around the axel areas where the wheels will later connect. Arches behind the wheel were created by extruding specific polygons these were then joined together centrally by welding meeting vertices.
Chassis Wheel Arch Area
Next a section was cut for the axel surround by deleting the required polygons above the wheel arch component. A slight curve was also introduced to the wheel arch object by inserting additional edges and manipulating the vertices accordingly.
Chassis Wheel Arch Area w/ Axel Hole
The axel holder itself was then fashioned using a tube object for the initial shape. The circular edge flow was then straightened to produce square edges which could then be extruded. The axel holder was then attached to the wheel arch object using the attach function and then welding the overlapping vertices. The edges of the axel surround were then curved by repositioning the corner vertices, it was then given more depth by "Shift-Dragging" the selected edges to extrude them. Lastly the gap between the axel surround and chassis had to be filled with a spacer object also responsible for holding the axel in place on a real steam engine. This spacer was produced using a standard box primitive, its polygons were then selected, extruded and scaled several times to create a right angular appearance.
Axel Area/Surround Creation
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(Click Images for Full-Size)
Completed Axel Areas
The completed axel area was then cloned and attached to the remaining drive wheel sections of the chassis. The entire group of chassis components were then mirrored and cloned for the left side of the chassis. The axles themselves were then constructed using simple cylinders which were scaled at either end to fit through the axel surrounds and wheels. The wheels produced by Steve Harwood were imported and then aligned to each of the six drive wheel axel areas. The individual parts of the chassis were also recoloured to provide a rough impression of the end colour scheme once the steam engine is textured.
Completed Axels w/ Wheels Positioned
The next step was to produce the chassis section for the front leading wheels of the steam engine. This was produced in the same manner as the main chassis however an arched hole was carved out using the "boolean" tool. The messy edge flow introduced by the boolean was cleaned up, otherwise this could potentially produce notable problems when both texturing and animating for example where applied materials may have evident seams across the object's surface.
Leading Chassis Axel Hole
(Click Images for Full-Size)
Angled struts were then created by extruding out polygons from either side of the leading chassis. These were then connected using the bridge tool to create additional polygons in the gaps left between the edges. A hole was then Booleaned through the joint struts to form the pivot point that enables the leading section of the train to steer. A similar hole was then made through the main chassis directly above the joining struts.
Leading Chassis Pivot Point Creation
(Click Images for Full-Size)
A connecting bolt was then produced using the cylinder primitive which was given a "Turbo Smooth" modifier to portray more of a realistic appearance. A nut was also constructed using the tube tool with only seven segments to represent the flat sides of a real nut. The border edges of the locking nut were then selected and angled using the "Chamfer" tool to remove the razor sharp edges which wouldn't be present in real life. The nut was also given a Turbo Smooth modifier which was slightly altered by inserting additional edges at either end to limit the smoothing effect. Both of these were then positioned between the two holes in the separate chassis objects to simulate their physical connection.
Pivot Point Connecting Bolt & Nut
Further detail was then generated by adding stabilizing struts which help in the steering of the steam engine in addition to keeping it firmly positioned on the rails. These again were created by simply extruding certain polygons on either side of the leading chassis section and were given a curved appearance by gradually rotating the newly extruded polygons.
Stabilizing Struts - Leading Chassis
The last major remaining portion of the steam engine's chassis left to construct was that of the trailing wheels section. This again was created using the same techniques as the other two chassis sections except rather than containing a pivot point, it is static and rigidly connected to the main body chassis. First one side of the chassis was made which was mirrored for the opposite side, then the lower portion was fashioned by extruding out polygons to create the necessary supporting struts and axel areas.
Trailing Chassis Production
(Click Images for Full-Size)
Final Chassis Preview Render
Before the animation testing can subsequently take place, the undercarriage piston & coupling features need to be modeled which are currently being produced by Steve Harwood. These will then be introduced to the existing chassis model and positioned as required. The majority of the individual components will remain separate for the time being and will not be group, as grouping can cause time consuming selection problems during the animation phase.
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