type of effect can be quite difficult to reproduce, especially with
some of the tread designs out there. Initially I was going to try
to reproduce a standard radial design, but the student I was teaching
that weekend (cheers Mike!) suggested not copping out and producing
a simple design.
I have recently been modelling out an Audi TT, producing the sports
tyre designed for this particular car seemed logical. A simple search
on a tyre manufacturer’s site, namely Michelin (in this instance)
generated an image of the tyre, albeit slightly small but still
on the Michelin Pilot Sport tyre as it fits the wheel of an Audi
TT, the initial layout and design of this tyre pattern would confuse
a novice modeller. But this doesn’t have to be the case. As
with any emulation task, simply break down the problem into it’s
core elements. For this particular tyre tread design, once the elements
had been analysed it was a simple case of recreating the tyre design.
so what elements have we got to this design? Firstly we’ve
got a uniform repeating pattern around the tyre. This pattern flows
from the outside edge of the tyre into the centre circumference
of the tyre, but the pattern distorts somewhat, like it’s
been grabbed and pulled around the inner circumference of the tyre.
The tyre’s side walls are also curved to meet the tread and
are also shaped to fit the wheel. As the pattern is mirrored on
the opposite side, once the geometry has been created on one side,
it can be easily mirrored on the other side using the Symmetry modifier.
how do we go around creating the geometry? Initially, a basic cylinder
primitive with the required number of iterations and height segments
is created and then collapsed to polygons so we can begin designing
the tread. As it’s a repeating pattern, all we need to do
is to work on one specific area, and this area can then be duplicated
around the cylinder, thus completing the tread. Due to the amount
of iterations set in the initial cylinder primitive, all we have
to do to design our tread pattern is to select relevant edges and
chamfer them to create a template for the inner parts of the tread.
To create these, a simple negative extrusion is performed and vertices
target welded to ensure the inner parts of the tread continue around
the side of the tyre.
the tread around the tyre is a simple procedure, but for this model
we are not going to use 3ds max 5’s symmetry modifier to distribute
it. The reason for this is due to the way the geometry has been
chamfered and welded. Adding a symmetry modifier will add extra
edges and vertices to the geometry which may not be present for
every tread piece, which if we meshsmooth afterwards will result
in an irregular-looking tyre! Therefore we delete the unwanted geometry
and rotate clone the tread object. Afterwards, we simply attach
all the tread pieces to the original tread geometry and weld the
adjacent vertices together, ensuring the centre side vertices are
also welded together. To create the stretched pattern around the
circumference of the tyre, the middle polygons are selected, and
with soft selection enabled, are rotated slightly. This will smear
the polygons around the tyre, thus creating the desired inner tread
pattern. The outer tread should be rotated the opposite way (also
with soft selection) to create the required tread pattern. The side
geometry is then extruded back way past the opposite side of the
tyre to form the inner part of the tyre that can be attached to
the wheel. Finally, a symmetry modifier is added to the tyre geometry
so the entire tyre is mirrored and welded. As this mirrors one side
of the object to the other, the inner tyre extrusion is also welded
and therefore forms a tube from one side to the next. If desired,
this internal tube geometry could be deleted as it will not be visible
once the tyre is assigned to a wheel.
a cylinder in the Left Viewport at 0,0,0 . I’ve used a
radius of 52.647 and a Height of 35.926 as these dimensions
fit the outline of the wheel on the image planes of the car
I am working on. Use whatever dimensions are relevant to the
image planes in your scene. Set the Height segments to 5 and
Sides to 80.
an edge loop along one side of the cylinder. Chamfer the edges
twice to create a curved edge. Select the innermost polygon
(the large one on the side) and move it inwards slightly to
create a slight inset.
edges running from the outside edge to the middle of the cylinder,
and select ones running around the cylinder’s middle.
Chamfer these a little as illustrated to create edges that we
can extrude back to create the template for our tread.
these new polygons back a little as illustrated. Target weld
vertices created from the extrusion at the outer edge to the
existing vertices on the outer edge as shown. Inset the inner
large polygon and collapse. Select the required polygons to
create a repeating pattern when rotated, invert the selection
and delete the unwanted polygons.
clone the object (not the sub-object polygons) 9 degrees and
enter 9 as the number of copies. Select the original geometry
and attach all copies. Select all vertices and weld them together.
Select the inner vertices (previously the large side polygon)
and collapse them.
the side polygons, inset, reposition inwards a little, inset
again and extrude backwards past the other side of the tyre.
Slice the tyre to add extra edge rings between the middle and
side of the tyre if desired. Select the middle ring of polygons,
and with soft select enabled (as shown) rotate the polygons
a little to distort the pattern. Select the outer ring of polygons
slice them to add and with less soft selection rotate them a
little the other way. Add a Symmetry modifier to mirror and
weld the geometry.
geometry. Additional chamfering could be made on the harsh edges
to smooth the tread out somewhat and meshsmoothed if the tread
has to be viewed at very close proximity.
get extra realism, I would recommend basing the tread on a tyre
that is suited for the car you are modelling. Most tyre manufacturers
have a list of tyres which are searchable by car manufacturer and
model. This particular tyre has been applied to an Audi TT wheel
in the final render as it was designed for this car.
To complement the wheel, try adding additional bump mapping to the
tyre’s side wall. Additional bump decals such as manufacturer
name, size, model, pressure information and any extra detail such
as lines and patterns that would be difficult (and pointless) to
model can be added this way to add extra realism to the tyre.
The final tyre texture should be a very dark grey around the tread,
fading off to a slightly lighter grey around the side wall where
the rubber is thinner and has accumulated dirt around any bump mapping.
The inner parts of the tread should also accumulate dirt and debris
from the road and should be added accordingly.
Due to the wide variety of treads out there, each tread design will
require a slightly different creation method. This may range from
different iteration values in the base primitive, different extrusion
patterns, slicing, chamfering (etc). It may require a different
modelling method depending on the complexity of the repeating pattern.
World magazine, Issue 41, August 2003.
Draper, August 2003. Reproduction without permission