stud/IV/notes.txt
Motiejus Jakštys 28bad3583f more notes
2021-03-01 10:36:55 +02:00

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Definition of a bend: ends of the line should always be bends, otherwise not
all line vertices are covered by bends (definition elsewhere).
Gentle inflection at the end of the bend: the article does not specify how many
vertices should be included when calculating the end-of-bend inflection. We
chose the iterative approach -- as long as the angle is "right" and the
distance is (greedily) decreasing, keep going.
Self-line crossing when cutting a bend: the self-line-crossing may happen
after a few bends have been skipped. E.g. ends of A<->B cross the line, but
"swallow" a few more in between:
,______
/ \
|___A | \ |
\ | B\ | __
\ | | | / \
/ | | |___,---,___/A |
/ | \_________________|
\ |
\ | \ |
/ / B\ | _ __
----/ / | | / \ / \
/ ,____/ | |___/ \___/A |
/ B| \_________________|
|
If a bend with 180+ deg inflection is found, its line between inflection angles
(AB in our examples) must be crossed with all the other bends to detect a
possible line-crossing. This is O(N*M), where N is the total number of line
segments, and M is the number of qualifying bends. In other words, can be very
computationally expensive.
This may be simplified: if other bend's endpoints (A' and B') are in the same
sub-plane as divided by AB, then the bend can be skipped from checking if it
intersects with AB. Some intersections may be missed (see the example), but
they will be eliminated by just joining A and B.