I would like to experiment with "multiple spaces" effects.
This is the first attempt ... screen space silhouette and volume trails. It evaluates ~realtime.
The silhouette trick:
- create array of primitive neighbours, preferably on the static geo
- transform the geo into the camera space (toNDC)
- almost flatten the geo in the camera space (@P.z). This exaggerates any normal angle "gradient" and flattens any peaks pointing to/from the camera.
- angle of neighbouring primitive normals to get the silhouette