Problems with hard and soft edges / corners + other stuff.

Hey guys, so I’m back to work on a dormant project and I’m evaluating the pros and cons of a starting over. I feel like starting over might not be a bad idea since I can certainly do a lot of things better / cleaner. However I’m still learning so I’m still unsure how to approach a couple problems.

First off, after doing some reading I get the feeling that certain areas on my model are to densely sculpted, that is to say I may have used to many loop cuts etc. to finely control the shape before subdivisions are applied (see the detail of the rudder cut out / tail section). Maybe it’s just me but I feel like on tight curves the mesh becomes over complex. Perhaps the solution is to use more separate parts to form one larger component? Making things to “monolithic” is partly a carry over from my auto-cad experience, which seems to be able to form a nice uniform mesh for pretty much any shape.

Secondly, I have had some trouble creating a simple mesh that adequately defines tight curves like those found around the corners of the canopy windows. Even after subdivision the result is far from ideal. Again I suspect part of the problem is making to much as one part. Should I for instance make the canopy frame separate from the “glass”?

Finally how should I approach hard edges like the edges of panels etc. (by “hard” I mean sharp points or corners)? I have been using the “crease” function to form a tighter corner / edge on the selected geometry. This works fine usually but also seems to add undesirable artifacts when I define a rectangular cutout (introduces hard 90° corners) on a curved surface. Is there a better way of doing this? Thanks for the wisdom guys!

Do you know about the rule of 3? Anywhere you have a major “bend” or corner, have 3 “loops”, one for the corner and one on either side to hold it. When you use a subsurf modifier (or similar, like multires), then when the “holding” loops are closer to the actual corner, it will be sharper and when they are farther, they’ll appear more rounded.

When doing a cut out, do a slight inset first. That will help you to be able to make it a little cleaner.

I’m not sure if you’re going for “realistic” or non-realistic, but Jonathan Williamson did a tutorial on CG Cookie last year or the year before where he did an airplane, and if I remember right, it’s not in the archives (meaning you can still stream it). If you’re a CG Cookie Citizen, it might be worth checking out that course series.

From my experience: definitely use the “separated parts” approach. The best way is to follow the technological divisions in the places you find it useful. For example: make in the fuselage just an opening for the cockpit. Then shape the windshield glass as a separate part, the canopy glass a separate part. Then duplicate these glass meshes and use them as the base for the canopy frames (these frames usually require much attention, because of all these roundings). Of course, the whole fuselage (less the canopy) can be modeled a single object, if it has an appropriate shape. (Split the airplane into separate parts only when it simplifies the modeling.[SUB] I saw some guys who split every panel into a separate object - it does not make sense. In general, use the bump textures to recreate panels. It is much easier way to do it, and keeps you model simpler[/SUB]).

Usually it is quite difficult to cut a rectangular hole in a curved subdivision surface, because the edges of such an opening are elevated. There are three methods (I ordered them from the most difficult to the easiest):

  • Prepare your mesh before you cut out such a hole. I start building the fuselage from a single bulkhead. On this bulkhead I place a vertex on the edge of the future opening. Then I place on the same profile two new vertices on the opposite sides of the first one, Together they form a part of the initial bulkhead: two collinear segments. Then I extrude this bulkhead into the fuselage. Then I can create a cut along such an edge without any deformation of the resulting subdivision surface. (This method uses one of the properties of this mathematical model). It is a good way to prepare large, important openings like for the cockpit or for the landing gear. (More about this method you can find in this book, in the sections about forming the cockpit and tailwheel opening);
  • Use Boolean modifier (in the Difference mode) to create an opening in the curved surface. Create an auxiliary object that matches the shape of the opening. Just for the convenience, assign it by the Parent relation to the object you want to cut, but place it on other, hidden layer. Add to the object you want to cut Boolean modifier in the Difference mode. Remember to place it after the Subdivision Surface modifier, so it will cut a hole in the resulting, smoothed surface. This method is useful from time to time for the openings for which method 1 would create too complex mesh;
  • Use transparency textures, combined with bump textures (to create impression of the sheet metal thickness around the opening). This method is the best for smaller, less important openings;

gradyp, when you say inset do you mean to extrude the edge of the cutout slightly in before creasing? I am going for as close to photo realistic as I can get. I have a good set of reference images so the only limitation will be my capabilities and time. I will also checkout that series.

Witold, those tips will be very helpful. On this airplane (f-100) the vertical stabilizer is somewhat blended with the fuselage, this was a sticking point for me on the first model for a number of reasons. The transition of the ‘dorsal ridge’ to the airfoil was particularly to difficult to pull off. My best guess is that splitting the geometry as shown by the green line would be easiest. Any thoughts on how to approach this area?