Ah, interesting. The Problem API 1 tries to take into account periodicity in establishing the world size and origin, although to be fair I don’t think this has ever been tried in combination with a DEM because we generally assume the DEM is enclosed. I assume you’re cutting off the DEM box walls in the periodic direction and have to adjust the size and origin because of this? Would it be possible to share what you are doing to see if the API can be improved to make things easier/possible without having to set things manually? If you have specific recommendations on how to improve the DEM interface you can also comment in this thread.
By the way, if you need to override the size and/or origin in only one direction you can limit yourself to that direction, leaving the other directions to be undefined/auto-computed, for example:
m_size.y = some_width;
m_origin.y = -some_width/2;
would only override the y direction and leave x, z to be autocomputed.