Modeling With Cross Sections

This tutorial demonstrates a method of modeling using splines to be transformed into cross sections to make an object in Max. Here I'll be making a wing but the same techniques can be used for many different things, even human figures. This method also works well for making objects for use in cutting out windows from fuselages or car bodys, ailerons and flaps from wings, elevators from horizontal stabalizers and rudders from verticle stabalizers using boolean cutting methods.

Step 1.

I have gleened the profile for an airfoil to be used as a background pattern and loaded it in to the left viewport. I am not concerned with any scaling at this time, that can be done later.



Step 2.

Maximize the left viewport and make a line object which replicates the profile of the airfoil. I try and use an even numbers of points. Here I am going to have 18 total. Points 1 and 10 will be at 0 elevation on the background. Once the profile is outlined and I am back to where I started, Max asks if I want to close the spline, YES I do.


Step 3.

Once the spline is closed it can be edited, moving points to fine tune the profile.


Step 4.

I made two lines to represent the leading and trailing edges... constructions lines so to speak.


Step 5.

Now I clone, move and scale the profile spline. Make as many clones as you need cross sections. If you need a different profile for a section make it the same way as the first just using a different backgrond image. Just keep your point count the same and the leading and trailing edge points at 0 elevation.


Step 6.

I have hidden my construction lines here. Now select the first spline and click on the "Attach Multi." button.


Select all your cross section splines then click the "Attach" button.


Step 7.

Now apply a "CrossSection" modifier to the first profile spline.


This forms a cage connecting point 1 to point 1, point 2 to point 2 and so on on each of the cross sections.


Step 8.

Now add a "Surface" modifier.


This will "skin" the cage. You most likely need to flip the normals and remove interior patches. The "Patch Topology" will control the density of the surface mesh. I am not sure how the "Threshold" spline option affects things. I just set it to something fairly low.


Now you can colapse the stack if you want. Scale as needed. If you need to add a cross section later use the slice plane in the Modify - Polygon sub object.