When would it be relevant to determine whether we have one or more than one intersection with a mesh? Wouldn't they usually just result in the same boolean response?
kevkang
I'm wondering if water interacting with light could be an example of the significance of multiple mesh interactions, such as with water just having light pass through or bounce around at the edge (as in a mirrored tank)
go-lauren
@nebster100
In terms of the inside/outside test, consider a point that starts on the outside, and a ray that goes from that. Since a ray goes to infinity, we know that we eventually end up outside the mesh. However, that means if we go inside the mesh, then we correspondingly must go out, so the number of crossings must be even. However, we can still go in and out multiple times if we have a mesh that is sort of folded on itself.
If we start inside, then we subtract one of the going ins from before because we are already inside, and then end up with an odd number. This is why we still need to count how many interactions there are with the mesh.
When would it be relevant to determine whether we have one or more than one intersection with a mesh? Wouldn't they usually just result in the same boolean response?
I'm wondering if water interacting with light could be an example of the significance of multiple mesh interactions, such as with water just having light pass through or bounce around at the edge (as in a mirrored tank)
@nebster100 In terms of the inside/outside test, consider a point that starts on the outside, and a ray that goes from that. Since a ray goes to infinity, we know that we eventually end up outside the mesh. However, that means if we go inside the mesh, then we correspondingly must go out, so the number of crossings must be even. However, we can still go in and out multiple times if we have a mesh that is sort of folded on itself.
If we start inside, then we subtract one of the going ins from before because we are already inside, and then end up with an odd number. This is why we still need to count how many interactions there are with the mesh.