3D Virtual Model

3D Virtual Model

As mentioned in the intro page, this modeling project exists in two versions; a physical balsa model at 1:20 scale, and a virtual 3D computer model.

The computer 3D virtual model started out as an unconnected series of individual 3D models created to make plastic parts for the physical balsa model, using a 3D printer.

Since I modeled several 3D printable parts for the balsa model, I decided to keep going and create a fully detailed 3D virtual model of the whole locomotive. It’s been a good Covid-lockdown project, as the full modeling process has taken ages… and the cab interior hasn’t even been started yet! When the cab interior is complete, I’ll use it to produce a 3D printed interior for the balsa model.

Working in Lightwave 3D

The virtual 3D modeling was undertaken in the Lightwave 3D computer program. For a detailed explanation of the process of modeling through to 3D plastic printing, visit the 3D Printer Parts and Lightwave 3D page.

The 3D virtual model could be translated to the real world at any scale with a 3D printer, or rendered out at any viewing angle as high resolution 2D images suitable for printing on paper.

Lightwave 3D is actually a 2-part program; Modeler, where all the model construction is undertaken in virtual 3D space, and Layout, where models are inserted into a virtual world 3D scene and rendered as finished images (see example images below).

The 3D scene may include one or more 3D models, 3D backdrops, or a photographic backdrop over which 3D models can be composited to give the appearance that the 3D model is part of a real world photographic image. A model can also be rendered with a transparent background so that it can be composited into other images in a program such as Photoshop.

The rendering process involves the Layout program calculating the interaction of light and camera optics, and how the viewer will see the final image with all of its component surface textures, shadows, reflections and a number of other ‘real world’ factors that we take for granted where ever we look.

The resulting rendered image can be a low resolution image for placing on a website, sized appropriately for TV or web video, or high resolution suitable for printing in a magazine or on a high quality paper print. In addition to static images, frame by frame animation sequences can also be rendered.

Modeling – Lightwave Modeler

To aid the modeling process, individual parts can be modeled on separate layers and viewed independently, with other layers, or as a whole model. Various levels of viewing complexity are also provided including wireframe, flat shade (where curves are displayed as their flat polygon components, and omitting any texturing that may have been applied to surfaces), smooth shade (showing smooth curves instead of flat polygons), texture (showing any surface texturing and colouring). Textures can be applied to any surface in the model, either as numerical surface settings, photographic and graphic images, or a combination of both.

In Modeler views, whilst the shapes are accurate, surface textures, light and shadow, reflections and so on are approximate; they do not show all the surface detail that will be realised in the Layout part of the program during final renders.

Below are some screen grabs of various stages of modeling parts of the larger loco model.

Main body modeling seen in wireframe shade mode.
Click image for larger view.

 

Locomotive long end side access door detail including louvers and latches. The doors partially visible at the top are the rear surfaces of the doors on the other side of the long end. In this wireframe view, individual polygons are clearly visible. All model geometery is made out of polygons, mostly 3 or 4 sided. Click image for larger view.

 

Bogie detail in wireframe and smooth shaded views. Smooth shaded view shows smooth curves instead of component polygon facets, and any basic colours that have been applied to surfaces. This view also shows the relative placement of the sandboxes and curved tubes which can dump sand on the railway tracks for extra traction when required.
Click image for larger view.

 

Connecting hoses and valves (one set at each end of the loco). Click image for larger view.

 

Staff exchanger wireframe detail view.
Click image for larger view.

 

Surfacing – Lightwave Modeler / Layout

To help identify separate surfaces, surface elements are given unique names to which colours can be added, some of which may be replaced by graphic imagery.

The usual workflow is to assign and apply surfaces in Modeler throughout the modeling process as components are created, but surfaces can also be modified in Layout at the rendering stage.

Some surface properties will not be properly visible in Modeler and will only be revealed accurately when rendered in Layout… a process that often takes a bit of trial and error to get just the right look!

In the images below, the green and pink surfaces have been replaced with ‘image maps’ of the VR logo and wings (drawn in Adobe Illustrator and converted to image files in Photoshop).  ‘Image Mapping’ refers to the process of applying an image to a surface of a piece of 3D model geometry.

Above: Surfacing in Modeler. Surface colours in Modeler can stay as they are, or be replaced by image maps. In this example, the blue, yellow and red horn interiors will remain, but the green and pink have been replaced by image maps of the VR logo and wings. The orange light surrounds have been replaced by blue and yellow image maps to correspond with the colours on the short end nose. The grey sides have also been replaced by image maps. Although the image at the right looks pretty good, it does not show the sort of detail that will appear in the Lightwave Layout renders.
Click image for larger view.

 

On the actual loco, the number plate is not a printed flat sticker, but a solid cast metal object with raised lettering and surround. Builder’s identification plates showing model and serial number are typically enameled (old ones are highly collectible), or an image printed on to a thin piece of sheet metal. In keeping with the originals, the X 31 3D model number plate is solid 3D geometry, not an image, but the small oval builder’s plate above it is a thin but solid piece of 3D geometry (to give it some depth, like a real piece of metal), with a photographic image applied to its outward facing surface.

3D Builder’s Plate and number plate. Click image for larger view.

 

Rendering – Lightwave Layout

Line view renderings. To achieve this, the surfaces of the 3D model were set to white,
and Lightwave Layout’s line rendering function was used to produce the 2D images.

Click image for larger view.

 

Test renders from Lightwave Layout. Top – flat shade, and below, experimenting with shadowing. At this stage only some of the model’s surfaces have colour; the rest of the surfaces are default grey.
Click image for larger view.

 

Early test render in Layout. The model is incomplete, requiring horns and pipework under the walkway, among other things. Click image for larger view.

 

Another test render to get the position of the yellow stripe correct. VR wings image maps to be added.
Click image for larger view.

 

Advanced Renders – Lightwave Layout

These are advanced renders of the exterior, which still needs rear view mirrors and other minor parts… plus I haven’t started modeling the cab interior yet!

Click images below for larger view.

Photographic Compositing – Lightwave Layout

In the renders in the previous section above, the loco has been placed on a large flat, thin rectangular ‘ground plane’ with a white reflective surface. The render view is determined by setting a virtual camera, which has the same adjustable properties as real cameras.

Lightwave can render models against photographic backgrounds; the virtual camera view can be matched to the original photo camera view, partly by matching the perspective of the model with that of the photo.

In the image below of the Layout render setup’s virtual camera view, the loco is sitting on the ground plane; the ground plane has been set so as to be invisible to the camera in the final render. However, the ground plane properties have also been set to ‘catch’ the shadow of the model, giving the illusion that the model is casting a shadow onto the ground in the photo.

Setting up a composite render in Layout. In wireframe virtual camera view, the black diamond pattern ground plane has been matched to the photographic horizon. The loco has been scaled so its wheel guage matches the railway track guage, helping to create the illusion that the loco is sitting properly on the rails. The orange circlular object on the right is a light which casts some light on the sunny side of the loco model, but its main purpose is to create a shadow on the other side. Invisible in this wireframe view, the loco shadow is cast onto the ground plane, but the shadow is clearly visible in the renders below. Click image for larger view.

 

A Bit of History

The location of the photos is on an abandoned railway line between Lilydale and Yering (east of Melbourne, Victoria, Australia), nowadays a walking and cycling trail. There are some old rails of sidings remaining at two of the former stations, Coldstream and Yering, which made the job of scaling the model and placing it ‘on’ the rails fairly easy. The images were initially composited in Lightwave Layout, then tweaked in Photoshop.

Motive power on the Lilydale-Healesville line was initially in the form of steam locomotives (up to 1964), followed by diesel-electric locos from 1952 onward. Rail Tractors, Walker Railcars and DERMs (Diesel Electric Rail Motor) also operated on the line.

As part of the railway line from Lilydale to Healesville, Yering Station opened in 1888 and closed in 1980. The section from Coldstream to Yering closed in 1983. The Lilydale to Coldstream section was used until 1991 for fertilizer delivery to the warehouse adjacent to the station platform. The Coldstream station buildings remained until they were destroyed by fire in the late 1990s. The fertilizer warehouse remains, partly visible in the renderings below. The remains of the abandoned main rail line between Lilydale and Yering was removed in 2019 to make way for the Yarra Valley Trail. Further past Yering, some abandoned tracks remain to Yarra Glen where a restoration project is under way by the Yarra Valley Railway heritage group for a tourist railway from Yarra Glen to Healesville.

Renders – X 31 at Coldstream and Yering Stations

Designed as heavy main-line locomotives (around 114 metric tons) , the X-Class diesel electrics never operated on the line, but let’s not let the facts get in the way of a good render!

X 31 at Coldstream Station. Click images below for larger view.

X 31 at Yering Station. Click images below for larger view.

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