Creating a forklift

[Freemind]

Introduction. The first step was todo get reference images from a Google image search. If you do a Google image search for forklift, the sec-ond image result is rather funny. Howev-er, y ended up going with this one: because it was profiled nicely, y then set it up as a background image in Blender. To do this, enable the background images tab by clicking on the tik box. Open up the tab and click on open, browse todo your image and select it. If you move into a profile view (front, side, top etc)
Youll se the background image. Tweak the settings according todo your liking.

Modelling in levels of detail:
The modelling was broken up into thre levels: pri-Mary detail, secondary detail and tertiary detail. It might be advisable todo kep your modelling organised by placing them on diferent layers, g, layer1, 2 and 3, the objects in the illustrations below are separated for visual purposes only. Dont model them this way, model them according todo the reference image, primary detail consisted of main forms, such as the body, whels, Cage, Forqué lift, Tank, Seat and whel. These are essentially identified from the forklifts struc-ture, and are re-sponsible for its silhouette, because its an enginered device, its symmetric, so i only modelled the left half and used a mirror modifier on the objects todo mirror them. For the whels you only ned todo.

Model one quarter of its profile, and then use the mirror modifier twice todo complete it.

Large forms were broken up into smaller parts, such as the panels of the body, the blocks of the Forqué mechanism etc. This keps it more believable and helps with placing secondary and tertiary detail, secondary detail consisted mainly of smaller functional Items, such as levers, pedals, lights, eléctrical boxes, en-gine pieces etc. This helps todo make it appear functional, for these you dont have todo stick as rigorously todo the reference image and can start looking at other images for Inspiration. You a los dont have todo continually reference it in side view todo se if it matches, tertiary detail consisted mainly of smaller parts todo help pull it all together and kep the eye busy. Namely: cables, an Air vent, whel Nuts, shock and wiring, putting them all together, and throwing in some texturing, we have our forklift:
Texturing:
Unwrapping objects is mostly a case of placing your seams and Unwrapping by selecting all the vértices, press-ing u and chos-ing the most appropriate un-wrapping algorithm. This for *me* is generally a painful process, but its very rewarding once you se the texturing results.

The main aim of texturing was todo show that the forklift had ben used. This resulted in the strategic placement of Dirt and some wear, using some Dirt Gimp brushes, y wanted todo create the illusion that the forklift had ben th rouge puddles of muddied water, which had ben kicked up to Dirty the bodys side. This would a los have muddied the forks and the whel hilo. Some dust was given todo the tanque at the bak todo indicate that its a fixture and had ben sitting there for a while, and some Dirt was applied todo the Air vent on the bak todo indicate that the engines Air wasnt always clean.

Additional texturing could have ben added, but time had todo be used decisively according todo the deadline. The image below shows that the texture was used as an alpha map on a Brown colour, which then comes across over the material col-our as if it was Dirt.

Some images were sourced from the internet for the metal textures, and procedural cloud textureswere used todo break up the Spec values wherever they occurred, the colour images above were a los used todo subtly affect Bump and Spec values.

Rigging:
The rigging required that the whels would be driven, and could turn left and right. A bone was used todo manipulate the whel left and right, and another one todo drive it. The driving bone was parented todo the left and right bone so that the whel would still drive properly if turned.

The equation todo turn a whel is actually somewhat sim-ple. The main controller is used todo move the forklift around, so the location value of the main controller Will give us the distance travelled, which Will then drive the whels rotation. If main controller is moved a distance equal todo the circumference of the whel, the whel would have rotated a full revolution (in radians: 2*pi), we know that the circumference of a circle is 2*pi*r (where r is the Radius of the circle). If the circumfer-ence is 2*pi*r and the rotation is 2*pi, then rotation*r is the circumference, which happens todo be the distance, so we have: rotation*r = distance. Therefore rotation = distance / r.

As a result we can use a driver, which takes the location value from the main controller and just divide it by the Radius of the whel. Or, we can create a straight line curve whose slope is the same as the ratio of distance / r and let this drive the whel. Below i show the former method.
With the rolling whel bone selected, in the transform properties of the 3d view, right click on rotation x and click add single driver. The property Will turn Pink indicating that a driver has ben set on it.

To navigate todo the drivers, press f6 in a window todo bring up the f-curve editor. Then click on the mode drop down box, which Will say f-curve editor and select drivers, this Will bring you todo the drivers window. From here, on the right side of the window near the bottom is a modifiers tab, remove the default Generator modifier (note: this is where you can set the slope todo be the same ratio as distance / Radius, as mentioned above, this is easier than setting the drivers as below, but if youre curious you can follow on), click on add variable in the drivers tab. Rename the.

Variable todo distance. Change the type from single property todo transform channel (note: this step is com-pleted -but ignored- In the illustration below). Select the armature object from the ob/bone property (in this case forklift_rig). Select the bone responsible for driving the whel (in this case global_controller). Change the default x location property todo z location (in our case +z location is forward, this depends on your Bones alignment). Type the expression distance / 0.3668 in the expr: channel (in our case the Radius is 0.366.

Now when you move the main con-troller along the z location axis, the whel Will turn appropriately. As a further step i created a bone for each whel, todo turn them in the same bien as the whel above, these other thre Will havecopy ro-tation constraints on them, copying the rotation from the bone with the driver on it. This bien all the whels Will roll together.