Architecturecraft 1.12-3.98 on forge 1.12.2-14.23.5.2838.

Almost certainly well into wishlist/feature request category, but IWBNI dynmapblockscan worked with architecturecraft. Dynmap-blockscan is an extension of dynmap that attempts to adds support for blocks provided by mods.

At the moment it merely remarks in the log:

[11:36:37] [Server thread/INFO] [DynmapBlockScan]: architecturecraft:assets/architecturecraft/blockstates/shape.json : Failed to open blockstate

The unfortunate result is that Architecturecraft blocks are currently rendered invisibly by dynmap.

This comment suggests that using the JSON-based model scheme is required to make this work. I hope this is not infeasible for you (but I'm not going to hold my breath :P). Info here on the data that the blockscan generates may or may not be helpful too.

Yeah, this is a huge Wontfix. Absolutely not our bug and not a reasonable assumption of a mod to make. Sorry about that.