The Complete Guide to Modeling Tires in
Blender
Skill level: Intermediate.
The screenshots will not always reflect the current state in the tutorial as I model ahead of the typing to make sure everything works correctly. This tutorial also does not go over basic Blender functions but I will explain those that may not be well known.
Delete the default cube. Insert a reference image of a tire as a background image in top view.
Insert a plane and scale it to fit one section of the tread.
Either using loop subdivide (Ctrl-r) or the knife tool (k) cut the plane along the edges where the tread will be extruded up. I did this be selecting all and doing a Knife (Multicut) with 14 cuts. Once the cuts are made move the newly cut edges down to follow the tread.
Go into face select mode and choose the polygons that will be extruded up. Extrude by region extruding up about .15 to .2 will be plenty of tread.
The 2 sections in the middle of the tread will run a continuous circle around the tire, so the faces on the front and back need to be removed.
The treads need to be beveled. Important thing to remember when modeling
objects is to not leave sharp edges; everything has some type of bevel. Adding these soft edges will give the model
an extra degree of reality. The best way to bevel the edges is using the bevel center
script. Start the script by going to
Mesh > Scripts >
This will replace the button window with the script settings. In Thickness set it to .034. Use face select for all the treads but the middle ones. The middle treads will only be beveled on the sides so use edge select for them.
Before doing the bevel on the polygons between the extrude parts there needs to be a few gaps to space out the treads. These extra parts will also help keep the mesh clean for the bevels. Edges need to be extruded all around the tread. I did an extrusion of .2 all the way around.
Select all of the edges around the bases, much like how the top section was beveled.
The edges of the tread need to be brought down where it heads into the side wall. Select the two top edges and bring it down close to the lower beveled edge.
The tread needs to be rounded as a whole since tires are not generally flat. This is easily done with Proportional Editing.
Turn on Proportional editing. Scroll to the center of the tread and select the four outer top vertices.
Go into front view. Press G to grab those vertices. With Proportional editing on a circle will appear in the grabbed area. Lock the grab into the Z axis and move the mouse up. The area within the circle will follow the four selected vertices. Using the mouse wheel scroll down, this will make the affect area bigger giving a nice fall off. The default proportional editing fall off is linear, sphere falloff gives a nice rounded affect.
Depending on how the gaps between the extruded areas on the top and bottom were done, they may not be repeatable. To ensure that there will be absolutely no holes an array of three treads will be created.
In top view leave edit mode and Add an Empty. Reselect the tread in the buttons windows and in the Modifier section add an array. Set the array like the following:
Select the empty and move it up, three treads will appear. Line the bottom of the second tread with the top of the first tread. When its close apply the array modifier making those elements part of the mesh.
Go into edit mode. The center space vertices (highlighted) need to be merged.
Blender can only merge the vertices two at a time with the merge tool. With my mesh that will be 88 vertices that will need to be merged. It’s a pain but makes everything better in the long run. The fastest way to do the merging is to box select the two vertices, pressing W for the specials menu, Merge > At Center. Once these menu options are chosen Blender will auto select them until it is changed, this makes it go quickly. In the center of the tread there will be vertices stacked on top of each other. These are all in a row. Box select that row and select the scale widget. Move the Y (green) down to the center of the widget. This will average all the vertices to be centered and aligning the vertices so that like ones are directly together. Do the scaling a few times. When it looks like they are all lined up select Remove Doubles in the Special menu.
There are gaps on the side that need to be filled in. Select the two vertices like the screenshot
Press F to add an edge between these vertices. With them still select do a subdivide to add a vertice at the midpoint of the new edge. Select these four vertices
Press F to fill in a polygon. There will now be a small triangle. Select the three vertices that make up the triangle and fill it in also. Do the same of the other side and the other 3 areas that are like this.
Once the vertices are merged delete the top and bottom treads, leaving what is similar to what was started with. The fastest way is to go into face mode and use paint select by pressing B on the keyboard twice. The result should look like the following.
This can be avoided at
the point when the edges are extruded out before the beveling the lower section. By doing the side ones
first then doing the top and bottom including the new edges. I find this way to be valuable regardless as
it shows some modeling techniques that would come in handy in the future.
The tread is now ready to be duplicated and made into a tire. Leave edit mode. Go into side view and insert a Bezier circle. The circle is going to be small compared to the tread, so scale up the circle quite a bit. I scaled mine by 13. In the buttons window in Curve and Surface select 3D to make the circle a path.
Select the tread and add an array modifier to it. Use the same settings as with the last array.
As long as the empty didn’t get moved, scaled or rotated, the top and bottom of
the tread will line up perfectly. Add
another modifier called Curve. In the
curve window in the
Back in the array modifier increase the count until the treads start to close. My count came to 51. There is a small gap where the treads don’t meet.
To close the tread select the circle. Press S on the keyboard and slowly scale the circle down until the tread closes. If a rim model is available it would be recommended at this point to insert it in to this file, just in case more or less tread needs to be taken out. It will also help with the side wall modeling.
There are two ways to do the side wall of the tire. One is to apply all of the modifiers turning everything into mesh. Then extruding and scaling the edges. There is also editing the original tread. I’m going to go over the latter version. Choosing to collapse the stack any extensive modification to the treads will be tough. Either save this as a different file or duplicate the tread, circle and empty and put them in a different layer.
Select the tread and go into edit mode. The tread is going to flatten out and makes it tough to get accurate view of the side wall. In the modifier stack in the array and curve editors enable the button “Enable modifier during Editmode”
Select the left and right edges there should be six of them. I made four extrusions then scaled them along X making it round. Depending on the rim and style of the tire will determine how the side wall will look.
Exit edit mode and press the Set Smooth button in the Link and Materials. If there are dark splotches and the tire just looks weird then the normals need to be recalculated. Go back into edit mode, press A, then Ctrl-N Blender will ask if Normals should be recalculated, go ahead and accept, the tire should now look correct.
