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A few decades ago I used one simple but very productive modelling feature in 3D Studio 4 for MS DOS (before it became 3ds Max). Namely, by assigning two mutually perpendicular 2D shapes in e.g. xy and xz planes as cross sections it was possible to create a 3D object very fast and simply. I cannot remember the exact procedure but I remember it was intuitive and easy. My question is if it is possible to do the same in 3ds max and how.

I know that lofting exist where one has to provide an array of two or more shapes in parallel planes as cross sections along a lofting path. Lofting needs much more time and work. I am not an expert in 3ds Max but trying to investigate and learn it.

EDIT: Here is an example of 2 cross sections from which one could create an airplane wing. The dashed line indicates orientation of cross section 2 in cross section 1. So, the cross section 2 is scaled based on the shape of cross section 1. cross sections

EDIT 2: Following the Eric Willis' answer and suggestion I made the wing using the 2-rail sweep method. The result is shown in the figure. The method makes surface without desired cornery outline, and there is no any parameter to make desired sharp corner, or at least I couldn't find it. Besides, the method is quite messy. One must make rails and the cross section using NURBS from beginning. Otherwise, if the rails are created from splines converted to NURBS, only parts of the converted NURBS are taken in making the sweeped surface (I don't know if it is a feature or a bug). So, unfortunately the 2-rail sweep is not the good enough method, as implemented in 3ds Max, for my question.

enter image description here

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  • You are obviously fighting against some really old fashioned user interface. Creating this i.sstatic.net/nmpGD.png has been fast (3 minutes) and trivial at least ten years in 3D software. Maybe I am wrong and you are talking of something which is at substantially higher level - for example of generating a 3D model of a human when there's available only side and front view photos ? What is it? Commented Mar 25 at 10:22
  • @EricWillis I updated the original post with a figure which illustrates what I mean. I do not have in mind such complex organic objects like human body. Creating an airplane wing from its 2 cross sections is a good illustration what I search for.
    – Igor Popov
    Commented Mar 25 at 11:27
  • took me a while to understand your drawing, I'm used to seeing cross section aligned with the main view (so the cross section 2 would be rotated 90º CCW)
    – Luciano
    Commented Mar 25 at 13:41
  • also it looks to me that the simplest way to accomplish what you ask is using loft, which is what you were doing before? Extruding a shape along another
    – Luciano
    Commented Mar 25 at 13:53
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    Looks like sweep. Dont remember. the loft of old 3Ds was quirky and might have been what your looking for as it didnt work like modern loft
    – joojaa
    Commented Mar 25 at 15:24

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I do not have 3ds MAX, but I have something to say about your dreamed simpler approach than lofting. I say "Forget it!"

Your 2 profiles do not define the 3D geometry without radical extra assumptions. See this image which contains a top view of 2 wings. enter image description here

Both of them have the same profile when watched downwards. Both wings also have the wanted "cross section 2" profile, only scaled to different sizes at different places.

The 3D shapes are different when watched from different direction:

enter image description here

Both of them are made by lofting through three surfaces which are scaled copies of your cross section 2. The surfaces were only placed to different elevations. Your 2 cross-sections do not give anything of that information, but it was included when I placed the surfaces for lofting.

Added later, maybe useless for 3ds MAX: Some programs have 2-rail sweep to extrude a surface to 3D solid along a curve so that the cross-section is scaled along the extrusion. An example:

The CAD program I use is simple. But it can extrude planar shapes to varying diameter "prisms". One must have 2 straight or piecewise straight sweep rails through the corners of the planar shape. The result is predictable as long as one has planar shape, straight rails and he doesn't attempt to extrude over more than one straight rail segment at a time.

enter image description here

In the left there's the top view. In the right there's a tilted view which shows your cross section 2 profile.

In the next image A shows the first extrusion.

enter image description here

B: The ending face of extrusion A is selected and extruded along the next straight line segment. The front side of the wing is a little short because the program stopped the extrusion to the ending point of the back edge.

C: The ending face of extrusion B is rotated to get the wanted top view.

The result is finally the same as what one could get by lofting, because the rails could have also vertical bends. I bet making such 3D rails needs at least as much tinkering as placing scaled shapes for lofting.

The extrusion above is the closest of your wanted version I can make. Check if your program has the same. Name "2-rail sweep" occurs in 3ds MAX tutorial videos but I have no way to check does it work in the same way as the simple version above.

Two rail sweep has variations in more complex programs. The next one is a sample taken from program Moi online user guide. The 2-rail sweep can be set to work so that rail 1 is the actual sweep rail and the other curve is used as the scaling reference rail:

enter image description here

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  • You made a good point. It is necessary to provide 3 (not 2) mutually perpendicular cross section shapes to have a uniquely defined 3d object. BTW, the simple approach is not dreamed. It is possible in 3D Studio before the Max era. Using this approach I modeled an airplane, a mix of Mig 29 (with its nice cobra-like nose) and F18 (with the fancy V shaped back wings) in a matter of 15 minutes using just a few 2d shapes for cross sections. Using lofting one would need to draw more 2d shapes for increasingly detailed 3d objects.
    – Igor Popov
    Commented Mar 25 at 17:09
  • If it existed and worked it had some fixed or editable rule how to generate the undefined dimension. The default could be for example "keep the center of the mass of cross section 2 in the plane of cross section 1" (a guess only). Commented Mar 25 at 18:09
  • @EricWillis yeah it was just a envelope scale control. But many cads do in fact still have this function But ist not really used as its not as useful as it sounds. Anyway maybe OP is using for 2-3 rail on generalized sweep instead (yeah names are nonstandard between packages, dunno what max uses since i havent used it in 20 years)
    – joojaa
    Commented Mar 25 at 19:12
  • @EricWillis Thanks Eric for your big effort. Unfortunately the 2-rail sweep method cannot produce the desired result. Check my EDIT 2 in original post.
    – Igor Popov
    Commented Mar 31 at 18:21
  • @IgorPopov 3ds Max has surely parameters which define what kinds of smoothing are performed in sweeping and other operations. Dig them up and try. Art modellers want smoothing for polygonal forms (rails, sweeped profile in this case) and they can be maximally ON by default (a guess). Start by searching for "sweep parameters". Commented Mar 31 at 20:48

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