The sweep function you ask for (taking different shaped cross-sections to make a surface that follows a path), can be done like this:
1. Create your cross-sections. It is ideal to make the first one, then make the other cross sections from the copy. This insures that your cross-sections match up when creating your surface.
- Use Surface Skin. You can specify if you want to Close it or not. You will need a surface that has subdivisions, and if you only have two cross-sections you will need to either use a polymesh with plenty of subdivision or use a NURBS, so you can insert rows of points afterwards. To make more subdivisions in Polymesh, use Effect/Subdivision. To add more points in the middle of a NURBS use Edit/Add point.
Note: For surfaces that have plenty of subdivisions, either BS surfaces or NURBS you can close off the ends by selecting it an then selecting Info/Selection. Then select Close top or bottom. This is different than the close on a skin or extrusion, in that it actually rounds of the end, sort of like the nose of jet plane. This saves a lot of head aches when trying to round stuff off with cross-sections.
Create your curve and Deform the suface with Deform/AlongCurve/Node/Create (Node is for one object and Branch means a hiearchy.).
Before you deform, do the following. Make the longest direction face Y. and then center the cross-section around 0,0,0. Then use Effect/Freeze. You do this because the deformatoin uses the relative position to 0,0,0 to place te object on the curve. The deform assumes Y direction of the shape is along the curve.
Once you defrom, use LCL (Local) at the bottom right of screen to allow you to translate along the curve in the Y direction. You can scale in the Y direction to make it longer or short. You can still use the other transformations, as needed, such as scaling in X,Z to make the cross-section bigger. Don't forget to switch back the Drag mode at the bottom right (this is the default for translation).
Note: if you need to work on the shape again, you can use Deform/AlongCurve/Node/Deactivate. This temproarily sets the object back to it's non-deformed position on 0,0,0. This makes it easier to texture etc.
I realize there may be a command in another product that lets you create you shape in one step. However, this method has many advantages, one being it is a breeze to texture. There may be a feature in Soft to let you do this directly too, but I've never needed such a function, because this way is superior. This is also the best way to produce an standard extrusion along a curve. . You are also set to animate along the curve, by saving keys for curve defromation on Y translate or scale.
Wheel and Tire.
This is sort of an open question, however I'll give some hints:
1. You can create you tire and wheel with a surface revoltion around an axis.
2. To make the wheel look like chrome, Apply the texture Chrome2 located in SI_Materials/Metals. Then use the mapping method Raytraced Refllection Map.
You'll need to specify that it is refelctive on it's material. When you render you should see a nice reflection even without much in your scene.
3. For the treads, it is most practicle to use a bump or deformation map. Make a tread texture in Photoshop of a couple of individual treads. Be sure it tiles well, so you can use it for all the other treads.
Note: For defromation mapping (Similar to bump mapping, but actually deforms the geomtry), you will need to render in Mental Ray. Also, most peope find their geometry does not have enough resolution to make the deforms. However, instead of making the geometry of the tire more desense, select it and use Info/Selection/RenderSetup. Then turn on surface approximation and Adaptive. Then change the value lower than 5. You might need to go lower than 1. However, remember the lower you go, the longer it takes to render. You may want to determine you value and then turn it off until you are ready to render final work.
Hope this helps,
Urp
