It comes back to bite you in a hurry. You don't need arbitrary precision to represent arbitrarily small things but to not have algorithms break down. Simple things like "is p inside the polygon" changes from true to false by moving both point and polygon 1 unit to the right. See under the heading "geometric predicates can FAIL" here http://groups.csail.mit.edu/graphics/classes/6.838/S98/meeti...
You are right that this happens only in edge cases. But you don't want that in a cad program if you have anything doing e.g point-in-polygon, triangulation or other such algorithms.
I know from experience that you really should bake this into the very foundation of a cad package (if you see 2003 me, let him know)
You are right that this happens only in edge cases. But you don't want that in a cad program if you have anything doing e.g point-in-polygon, triangulation or other such algorithms.
I know from experience that you really should bake this into the very foundation of a cad package (if you see 2003 me, let him know)