I sometimes run into strangeness with these brushes where they curve across a flat surface. Sometimes they work perfectly and sometimes they insist on shooting at an angle.
When shot at a flat surface with a smoothing group, the leaks sometimes do not go straight down; they curve awkwardly.
My issue here is that the particles follow the normals of a smoothing group. For the leak brushes and things, the leaking is supposed to go straight down. But if used on a baked flat surface, the particles will curve, no matter what setting (even "Normal Factor" doesn't do anything and actually makes it worse). It doesn't always do this though, so I believe it may be relative to the size of the polygon?
The only workaround I have to make the leak particle brushes work against a flat surface every time is to import a flat-shaded version of the model.
I'm curious if there is something I'm missing that would make particle brushes work better when shot at a flat surface that has a smoothing group.
