Required metric propagation

[Algiane]

Propagation of metric at required points:

• if prescribed size at required point is larger than the neighbouring size, we have to increase the size at neighbouring point
• if prescribed size at required point is smaller than the neighbouring size, we have to decrease the neighbouring the size at neighbouring point
• we want to propagate by advancing-front from the required points toward connected vertices, then touched vertices toward the next layer of connected vertices, etc.

Questions:

• how to deal with collisions during the propagation ?
• how to ensure adaptation convergency of size map with the combination of classic and required gradation ?