Tutorials

Summary

Modeling car rims is actually fairly easy and straightforward. This is because there always is some sort of symmetry, always. Whether it be point-, line- or suface-symmetry, there's always one or a combination. This will reduce modeling difficulty and effort tremendously, since Max has, since version 5, the Symmetry modifier which is very handy.

The Rim and Symmetry Analysis

Well before jumping in I think we should first pick a rim which we'll try and recreate.

After browsing to one of my favorite rim makers, Toora, I picked one out which is as good an example as any:

Do realize we will probably not be making all those nuts and bolts, maybe if I have some time at the end.
Anyways: as you can see, there is a five-fold symmetry here. 5 Center nuts and 5 arms. So what we are going to do is modeling one arm, one nut hole, one bolt / nut and 1/5th of the outer rim and that's it. Nothing more. No way that I am going model the whole thing. We are going to let the Symmetry modifier do all the work for us.

Okay I've drawn some of the symmetry options that are available in the next image:

Immediately after I drew this, I realized: there's not only a 5 fold symmetry (the red and green part), but even a 10-fold one (the blue part)! So all we have to do is model a part of 36 degrees (360 for a total circle, divided by 10) and symmetry it so that it makes up the entire rim. I have been very lucky choosing this one as you can see... Would this rim have 5 arms and 6 nut holes then it would be way, way, way more work, it's then when you start cursing Max and wished you used Rhino. But that is not the case and it hardly is, as said, there is almost symmetry on every rim.

Start: Outline and Basic Shape

I talk a lot about basic shapes with which I mean that I always model something that roughly looks the way I want it to look and then start detailing and refining. I see many modelers work in a different way and that is cool, but I feel that my method is especially good when you want to learn and also works well for finding errors or misformed parts of your model more easily.

So first a rough outline which we will use as guidance. In the front view I create Circle with a radius of 100 (1)(remember that in 3D modeling everything is about relative sizes, not absolute sizes, so 100 is absolutely arbitrary, but handy to work with) and a cilinder with radius 100, both at position 0, 0, 0 (2). In the Cilinder set the height to something like -30, height segments 1, sides 20.

Now for a bit of math. I said that we will only model one part of 36 degrees. So click the 'Slice On' radio button of the cilinder. In math the 0 degrees line is at the middle right (1). So for example slicing from 0 to 90 gives result (2). We want a total of 36 degrees and I want it at the center top. So we slice from 90 + 36/2 = 108 to 90-36/2 = 72 degrees and hooray, it works as expected (3). Hm, but now that I think of it: having it at the center top isn't handy, because what we will be modeling is only half an arm of the rim which I want at the center top at the end. So we shift the slicing 18 degrees. Slice from 90 to 54 (4) This may look like nonsense, but it'll become clear very soon.

Let's have a test run at how the symmetry modifier will help us out. Add one (1), and if everything is correct it should be at the right place and angle already. Add another one (it will be at the same position and angle as the first one) and rotate it (in the sub-object of the modifier, yes modifiers also have an SO, usually for editting their Gizmo's) 36 degrees. This is best done by clicking the 'Absolute Mode Transform Type In' which then becomes 'Offset Mode Transform Type In' button at the bottom center of your screen. This button changes the amount you give the rotate / move / scale from absolute to relative. When you set it to Offset, it adds it (the amount you want) to the current value, which is what we want now. This way you save yourself calculation time. :) So fill in 36 in the Z-direction (rotate!!, not move) (3). As you can see we are not yet at 10 parts, so add another one, rotate this one 72 degrees (twice the 36 of last time) (4). Now comes a part where you might think it'll go wrong: we are going to add another Symmetry modifier. This will result in 16 parts in total, while we only wanted 10. But the modifier has a Threshold, so it will symmetry it over the ones you created in the first couple modifiers and weld them away. They won't be seen. So add, rotate 144 degrees (5). In the last part of the next image I show how your modifier list should look right now (6) And also the Transform Type-In thingie.

So far for the boring part, now it's time to take advantage of what we just created.

Copy the original circle and give it a radius of about 35 (1). This will work as a guidance when we model the center part. Then copy it again, set the radius to 10, move it to make the guidance for the nut holes (2). Now I drew a line (with Initial Type 'Smooth' and Drag Type 'Smooth') to help as guidance when modeling the arm (3).

Modeling

All outlines are set, so we can now start modeling. Back to the original cilinder, click the 'Show End Result On/Off Toggle' so that you only see the single part (1). Set the Sides to 3 and Cap Segments to 3 (2).

Now we want to have an EP (we want to model!!), but we have a cilinder, that's tricky since we have all those modifiers and don't have the option 'Convert to Editable Poly' without collapsing the modifiers along with it. But Max is to the rescue, it has a nice copy/paste function for modifiers. So select all the symmetry modifiers by Ctrl clicking them and then right click, Cut. You modifiers are now cut and placed in memory just as it would work with text. Then convert your cilinder to an EDITABLE MESH (!!) and then to an EP (somehow Max fucks up if you convert directly to an EP), right click it in the modifier panel (where you just clicked Cut) and click Paste.

Before we go into the VSO, go to the PSO and delete the sides of your sliced cilinder (3 + 4), they will give troubles when using the symmetry modifier, and the rear part too (5). So now we have a total flat part of the original cilinder. Into the Vertex Sub-Object we go now, we want to shape it (6)!

So modeling now, but first set the interpolation of all circles created to 'Adaptive', this way they're perfectly smooth and better guidance.

In the VSO start moving the vertices around so that match all your guidance lines (1) and delete what you don't need (2). Click the 'Toggle End Result' button to see whether we are getting somewhere (3). I think we are! This is starting to look like something and all with very little effort. You could work with the TER button On all the time, this is a very good way to see the result of what you're doing immediately and all over the whole rim (especially with an MS modifier of course).

So do a little editting of vertices and slicing to make it fit better (1 + 2) and we're done for the moment. What we have now is an almost perfect 2D representation of what we want in the end. From now on things will go faster: you have the knowledge know of how to setup the symmetry and then all you have to do is model one bit perfectly and you're set. I changed the shape of the outlines since I noticed the rim was getting too fat compared to the original, editted some more vertices (2).

The next thing we will do is make the nut hole. Go to the PSO and slice the shape so that it matches your guiding circle (1). Cut some additional lines to prevent errors later on (2) (keep your mesh tidy!). Select the polygons that make up the hole and extrude inwards (3), delete the polygon in the middle that you just created, you don't want that, once again because of the symmetry modifier.

Now in the ESO select some edges that make up the side of the arm (1), to give it thickness, by shift-dragging them (2), and the end result should look someting like this (3):

All to do now is chamfering edges to define the shape better and 3D the whole lot to make it more look like the original. I am not going through all those steps it would be a repitition of previous tutorials and also a lead-by-the-hand type of tutorial which I don't like. Tutorials should be about concepts not step by step explanations. This is what I got after 5 minutes of editting and chamfering etc.:

Either you call it a day here, or you make one final addition: the outer rim cilinder. This you could make separate from the part we just made or make it a whole. We'll try the latter.

I didn't change much at the top end of the arm and so you shouldn't have too much trouble folliwing the next steps. Create a tube with radius 100 and 103, same slice as before (90, 54) or at least make it fit the rim (1) and then delete all polies except for the inner ones to be left with a small strip (2) then delete the last polygon (3), attach the rim to this tube part and weld some vertices to make it form a whole, then select some edges and shift-drag them (4 + 5).

Some more chamfering and shift-dragging where need and you should be all set. Then you should (or could :P) have something like this (1) and I can think you can do the rest yourself now! It may not resemble the original perfectly, but you only have to change one single part...

And here an example of a little more worked out rim, with a semi-nice texture.