Modelling a tire

[Bressan52]

I´m used to model a car wheel, or a tire, with the sketch revolution. Thats ok.
But to add the "tire treads", I got stucked. My approach is design the tread at a sketch plane tangent to the "basic clean tire".
Then pad the sketch, and do a polarpattern to this pad. But I´ve tried a lot, read the help and faqs, tried another transformations... and no success to figure out how to command the revolution around the right axis.

The file is attached, any hint welcome.

OS: Windows 7
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.15.4671 (Git)
Branch: releases/FreeCAD-0-15
Hash: 244b3aef360841646cbfe80a1b225c8b39c8380c
Python version: 2.7.8
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[r-frank]

Hello Bressan.

Polar Pattern only works when you use a pad (or pocket) with a sketch bound to a face of a solid.
In that way FreeCAD will automatically fuse the Pad with the "base solid" and polar pattern is possible.

In your case your revolution and your pad are two different solids.
Therefore you must use the Draft-Array-Tool (and then do a union on both solids).

Roland

[ppemawm]

But to add the "tire treads", I got stuck

One way to accomplish this is to use the DRAFT workbench POLAR ARRAY: http://www.freecadweb.org/wiki/index.ph ... raft_Array
The input for the Draft polar array is shown in the Data tab on the figure below. I used an array of 50 patterns about the X axis.
Please see the attached file.

tire_tread.FCStd

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OS: Windows 8.1
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.5958 (Git)
Build type: Release
Branch: master
Hash: b3e0e8272f0ed017caf7644808e929c87a85937e
Python version: 2.7.8
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[Bressan52]

Many many thanks for enlighten this issue! Will practice with the draft-array!

[Bressan52]

I did a lot of sucessfull tire patterns in the last weeks, thanks to the hint about the draft array feature.

Now, a new defy is to write the letterings on the tire sidewall. I read about the draftshapestring text feature, but understood that is not ok to do a text following a circular path. Any suggestions of methods to this task?