That’s the only viewer that I’m aware of that supports annotations.
Coming back to this five years late, because that is no longer the case — at least on Android.
SRD Android CAD Viewer opens a .3dm directly on an Android phone or tablet. Rhino’s own file reader runs on the device, so the drawing is rebuilt rather than converted: model space and every layout tab, with dimensions, leaders and text resolved to their effective style, hatches at the scale Rhino generates them, and detail views. A layout is treated as what it is, a print preview, so anything set to “no print” stays off the sheet.
Ryan, your stack of printouts is the case this was built around. The .3dm goes to the shop instead of the paper, and the dimensions that are already in the drawing go with it.
Max, on your offline question: the file is read on the device. No account, no upload, no connection at any point. That is a deliberate choice rather than a missing feature — every option suggested in this thread puts the model on someone’s server first.
Where it will not help you: it draws the 2D drawing, not a shaded, explorable 3D assembly. It does not model and it does not edit. It does not measure either — you can read the dimensions that are in the file, but you cannot pick two points and get a distance. An exploded view still has to be exploded, dimensioned and laid out on a sheet in Rhino; what changes is that the sheet then travels on a tablet instead of on paper. And it is Android only, so it is not an answer for anyone in this thread on an iPad.
Disclosure: it is my own app, free to download today. Screenshots, a short video and the download link are in the announcement here:
Android 5.0 or later, 64-bit ARM. If a drawing does not come out the way it looks in Rhino, send me the file and I will look at it.