I have some older lidar data that was collected in some irregular shapes. I'm creating some terrains for this data from the multipoint data and would like to avoid triangulation across concave edges by using an outline polygon feature class as a soft clip. What I have been doing is buffering the multipoints by a positive distance, dissolving any internal polygons that were created, then buffering the new polygon by same distance as step 1, but a negative number. The problem is that the first step, buffering the multipoints, can take a long time for big files. Is there a more efficient method? For some of these multipoints files and in cases where I'm going to use several adjacent multipoint files in the same terrain, I think I might find that just digitizing an outline might be more efficient than my buffering method has been.