The purpose of this tutorial is to explain how the smoothing is working in rFactor and how you can manage this feature with 3DSMax.
First, here are few explanations about what is a smoothing group : it's a group of polys without any edges visible (if all polys are attached together obviously). 3DSMax can manage 32 Smoothing Group per 3D object so it's quite easy to create visible edges when needed simply by assigning a smoothing group to a bunch of faces.
but, rFactor can only manage one smoothing group so we need to find a trick to get a good result without multiple smoothing groups. Here is what I'll detail below.


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This first picture shows you the goal of this tutorial : 2 quite basic shapes with sharp angles. To build the shapes themselves, just create a box and a plane (4x4) and then extrude the 2x2 plane in the middle to create the 3D.


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Once you've converted those both shapes to mesh, just select all faces. You may notice several smoothing groups have been created automatically by 3DSMax (here 7 SG). This is relative to the basic objects we used (box and plane).


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Here, the number of smoothing groups is now 3. I just push the [Autosmooth] button and 3DSMax automatically optimized the smoothing groups. As you can see, it's not perfect : our final goal still remains 1 single smoothing group.


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Now, select the 8 faces from the extruded part. You can notice that 2 smoothing groups are used for this part. Those small examples show you how MAX is assigning his smoothing groups.


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Here, we force the software to use only one smoothing group. To manage this operation, just follow the operations below : 1.select all faces 2.press the [Clear All] button 3.select the smoothing group #1 You can look at the result : it's quite ugly and far from our goal. But it's what you'll get in rFactor if you don't modify anything on the 3D.


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Now, we'll begin to improve the smoothing. Just select the 4 faces of extruded shape back. Click on the [Detach] button in the right-click menu or in the right column. Select [Detach To Element] and lick the [OK] button.


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You can look at the differences with the screenshot above. The white shadows are more realistic now.


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Redo the same operation on the selected faces to detach the extruded part from the base plane.


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Now, the 4 planes of the extruded parts are still smoothed together. To improve that, just select the top and the bottom faces (or the left/right) and detach them again.


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Now, this part of the object is perfect with realistic shadows and sharp edges. The box shape can be modified in the same way to reach this result.


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Just to check thing, redo an [autosmooth] on all faces. Only one smoothing group is now used by 3DSMax.


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This screen just explains you what happens on vertices. Here, you can notice 3 vertices have been created instead of the single one before the [Detach] operations.


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Here is a little new example with a cylinder. The first object on the left is rendered without smoothing. The second object on the middle is rendered using one smoothing group. The last one (on the right) is rendered using one smoothing group but after having performed [Detach] operations.