Smoothing groups are one of the most frequently requested features for 3D World Studio, so I am happy to show you their implementation in Leadwerks3D, finally. Smoothing groups are usually stored as a bitwise flag. When two faces share a vertex at a certain position, if they have one or more smoothing groups in common, their vertex normal is calculated as if they are sharing a vertex.

I first attempted to write an algorithm based on edges, which worked great for cylinders but failed for geometry that had faces that influence vertex normals they are not connected to by an edge. I wrote another routine, which uses an n*n*n loop (big programming no-no, but sometimes it's necessary) and got good results with cylinders and spheres. Cones are a difficult case, and if you don't believe me, just crack out a cone in your favorite 3D modeling app and inspect the tip. I got around this problem by adding a max smoothing angle member to the brush class, which allows the smoothing algorithm to discard faces that are too 'different' from the one being processed.

Here's the result:

In order to make shapes like arches appear smoothed, the smoothing algorithm has to span multiple objects. This will be accomplished by first grabbing all the brushes in the nearby vicinity to the brush being processed, and then searching for vertices that occupy the same position, on faces that have a smoothing group in common.

In the past, we've seen some pretty advanced modeling done with 3D World Studio, but the lack of smoothing groups always limited it. It will be awesome to see what people come up with, when those limits are removed and they can model exactly what they want.