why does un-trim work and merge with original sometimes works what's the rules for this how do I know when this will work and when it will not only works about a 1/4 of the time.
Travis,.. un-trim can depend on a few things and it does have limitations...
- with the "Merge with original" check, the parameters which define the boundary maybe limiting in how the boundary extends/untrims.. and/or what/where/how you choose the edge(s) or faces can help (or not) with how it un-trims (or does not).. so, uncheck if it cannot extend or copy the surface to make it independent from the adjacent surfaces.
Travis,.. un-trim can depend on a few things and it does have limitations...
- with the "Merge with original" check, the parameters which define the boundary maybe limiting in how the boundary extends/untrims.. and/or what/where/how you choose the edge(s) or faces can help (or not) with how it un-trims (or does not).. so, uncheck if it cannot extend or copy the surface to make it independent from the adjacent surfaces.
...otherwise, try using Extend and Trim.