I wrote this tutorial in 2005 while I was doing lots of car parts Modeling
Hope someone can still benefit from it

The purpose of this white paper is to present a technique for modeling a car tire using various Polygon tools.

Sample tire layout.

Examine the tire layout, notice that it’s somewhat repetitive in the Y direction.
The idea is to find the portion of the tire that could be successfully repeated to produce the tire as if it was flattened out.

The repetitive portion of the tire.

Note: a close look at actual tires will reveal that the blocks change is shape and size, for more diverse blocks modify the repetitive portion as long as it occupies the same space.

Step 1 : Adding the Image plane
Add the tire layout image as an Image plane in the Front view.

Image plane settings.

In the attribute editor of the image plane, choosing Display “looking through Camera” will insure it won’t show in other views.

Image plane Placement.

In the Placement Extras section
Put these values in the Center Attribute: 0, 0, -1.0,
this will make it easier to view the polygon in the front view.

Polygon Plane.

Step 2 : Blocking the main shape
Start with a polygon plane.
Subdivisions Width 16
Subdivisions Height 2

Move the Vertices until you get an approximate match of the repetitive unit.

Adjusting Vertices.

Switching to X-ray Shading in the front view will allow you to view the image plane in the background.

Adding Subdivisions.

Add more Subdivisions.
Edit Polygons > Split Edge Ring Tool
Note: to adjust the position of the new edge. Open the INPUTS node under the channel editor and modify the PolySplitRing.

Adjusting new edge position.

using the Split Polygon Tool, start adding more edges to match the tire treads.

Adding more edges.

Fine tuning.

This is how the faces that are ready to be extruded look after using the basic poly tools.

Deleting unnecessary edges.

Note: there are some edges that are not adding value to the model, this mesh is not going to be animated so continuity is not a huge factor at the moment,
however edges must be continuous in the repetitive phase as you will see.

Instance copy.

Make an Instance copy of the model and move it on the Y axis.

Step 3 : Continuous Duplicates
It’s really important at this point to make sure that the duplicates will align perfectly with each other, hence the use of an Instance rather than a copy.
With the instance copy used as a guide move the Vertex from the original surface until you achieve perfect continuity.

Adjusting the instanced copy.

Some of the faces now don’t match the image plane, which is OK at the moment because you can go back and adjust each unit individually after the duplicate phase.

Delete the instance object.
Pick the faces as that mach the image plane.

Step 4 : Extruding faces
Edit polygons > Extrude Faces

Extruding Faces.

Click on the manipulator toggle to change to extrude on an exact axes.

Extrude adjusted.

Extrude the faces on the Z axes.

Final Extrude.

Repeat the previous steps to extrude them one more time.

Final Extrude.

Repeat the previous steps to extrude them one more time.

Edges Collapsed.

Edit Polygons > Collapse.
Repeat he previous process to the other side of the tread.

Step 5 : Adding Curvature
Looking in top view, you will need to align the Vertex on the side.

Top View.

Pick the Vertex on the sides and click on the Manipulator for the Z axes (so it will only move on the Z axes)
MMB click on any Vertex in the middle so it will align automatically.

To get curvature for the treads from the top view , you will use a lattice deformer.

Adding a deformer.

In the Animation menu
Deform > create Lattice
in the SHAPES node change the lattice to the following
S Divisions = 5
T Divisions = 2
U Divisions = 2

Top View.

From the top view, move the lattice points to achieve the desired curvature
Delete the object history at this point to get rid of the lattice deformer.

To insure accuracy for the next step, make sure to freeze transformation for the tread.
Duplicate the tread as an instance and move it on the Y Axes until it aligns perfectly with the original, notice the value of the translation in the Y axes (in this case it was 10.63).

Overlapping faces.

Delete the faces that are overlapping with the instance tread that will insure contuous edges.
Note: Display > Custom Polygon Display > Highlight Border Edge option, will allow you to better visualize this process.
Step 6 : Duplicating the tread
Open the duplicate option box
Edit > reset Setting

Duplicate settings.

Translate 0, 10.35, 0
Number of copies 34 (this number will vary depending on the size of the actual tire, for accurate results count the actual blocks on the tire from the side view)
Note: at this point you can modify the copies to get randomization in the block sizes as long as the connected edges are not moved.

Polygons > combine

Polygon Combined.

Now the treads are one mesh, you can merge edges, since the Vertices are somewhat perfectly aligned.

In the front view, select all the Vertices and choose
Edit Polygon > Merge Vertex > open the option box and choose Distance 0.005.
If you still have edges that are not connected, you can either increase the distance in the INPUTS node or use the merge Edge tool.

Adjusting faces.

It’s important at this stage to have a look at the treads to insure continuity and no over lapping faces.

Step 7 : Bending the treads
Animation menu, Deform > create Non Linear > Bend
Note: since the image plane was assigned to the front view the bending deformer needs to be rotated 90 degree on the Y axes.

For the curvature find the degree that will insure a perfect bend so the top and bottom edges meet.

Deleting history.

Delete the history to get rid of the Bend Deformer.
Merge the Vertices to have a continuous mesh.

Modify > Center pivot
move the tire to the Origin 0, 0, 0
Modify > freeze transformation

Adjusting mesh.
Step 8 : Building the Tire Side Walls
Select the outer edges for both sides
Edit Polygons > Selections > select Continues Edges.

Picking Vertices.

Ctrl + RMC and choose ‘to vertices’
scale the Vertices down, and then scale them again on the X axes to move them away from the tire.

Pick the final gap edges and collapse them, to make it easier to extrude the outer edges later on.

Picking edges.

Collapsed edges.

Repeat the previous steps of the other side of the tire.

Select the outer edges for both sides
Edit Polygons > Selections > select Continues Edges.

Outer Edges.

Edit Polygon > extrude Edge
Click on the manipulator toggle to change to extrude on an exact axes.

Scaling Edges.

Scale the extruded edges down.
Repeat the previous steps to get the side wall as in the picture below.

Modeling the side walls.

select an edge and add another ring to the side wall
Edit Polygon > Split Edge Ring Tool

Adding more edges.

Select the inner small edge that was just created
Edit Polygons > Selection > Convert Selections to Edge Ring
Edit Polygons > Selection > Convert Selections to Faces

Adding groves.

Extrude the selected faces in to create a small grove.
Step 9 : Tweaking the tire
Select various rings scale, move and rotate to final tweaking
Select all the edges
Edit Polygon > Normals > Soften/Harden
Angel = 30

Final render.

Conclusion
Modeling doesn’t entirely mean you should use only modeling tools from the Modeling menu, as you see Deformers can play a major role in the modeling phase.

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This entry was posted on Monday, January 23rd, 2006 at 4:07 pm and is filed under Maya. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.