We have created a terrain cutout/carving HDA for 3dsmax. HDA is really unstable in 3dsmax at the point even trying to delete the HDA from the scene, it crashes 3dsmax. Terrain we are trying also has a max polycount to 400k.
I am attaching 3dsmax file which has a Terrain and pieces to cut/carve and also HDA.
We don't have a specific steps that its crashing as its doing it randomly but here are couple of things to try:
Method 1:
1 : Create HDA object and add Terrain and One of the piece.
2: Bake out Mesh.
3 : Use Bake out mesh in the HDA and add second piece. Try to enable/Disable “Show Only Cutout Piece”.
Mathod 2:
1 : Add HDA as an modifier to terrain piece.
2 : Add 2 piece to cut out.
3 : Try to use the same param “Show Only Cutout Piece”
Here is another bug we found where resetting xform removes generated mesh created by HDA.
Again there are not specific steps but in general, try to use the HDA and you will see where its crashes.
If you need more info, please let us know,