Author Topic:   inter-mesh cracking
posted November 23, 1999 08:32 PM            
roam prevents intra-mesh cracking nicely, with forced splits, but i was wondering what approaches people had taken to prevent inter-mesh cracking. I would imagine that with a good screen-space distortion metric, you could alleviate a lot of the visible cracking (ie, anything that would crack badly would probably get split), but from a more academic standpoint of completely eliminating any inter-mesh cracking, what approaches would be good, assuming an implicit-array based implementation. or is it even necessary to worry about?



LDA Seumas
posted November 24, 1999 12:32 AM           
What do you mean exactly by "inter-mesh" cracking? Do you mean where two binary triangle trees meet at the edge, or where smaller meshes sit on top of the terrain mesh?

For the former, it works to connect the edges of the different binary triangle trees with neighbor pointers at the beginning, and then forced splits will properly propagate between the many base trees and keep things crack free in the same manner as with only one base tree. (Remember that starting with a diamond over a landscape is essentially two separate but connected binary triangle trees to begin with.)

For the latter, one option is to run a separate pass over the terrain to add extra refinement to areas that have objects sitting on them. I don't do this myself, and haven't found it necessary, but I can see it being useful for a lot of slower moving applications.

-- Seumas McNally, Lead Programmer, Longbow Digital Arts