[ilCosmico]

DwgPrototype1bReader.readDataFields reads the (segment index, size) pair of a blob page, jumps to that blob01 segment and reads its data, but it never moves back. From the second page on, the next pair is read from inside the data of the previous page, the segment index is garbage and the read throws an ArgumentOutOfRangeException. The exception stops the whole section, so every ModelerGeometry in the drawing ends up without AcisData.

It happens as soon as one ACIS payload needs more than one blob page, a little over 2 MB in the files I tried. I hit it on a 2013 DWG with a solid stored in 7 pages, and I could reproduce it with a single extruded polygon with a lot of sides.

The loop now saves the position after the pair and goes back to it once the page is read. With the fix the payloads match the ones from the obsolete DataStorage reader, on that drawing and on the other 2013+ DWG files with solids I have.