Yes angles pose a challenge for me on every job. So, my workflow for angled sheathing, like roof sheathing is to use the Materials Tab OR the area takeoff tool that comes with Estimator.
For my roofs, for example, I model sheathing and then I model the shingles on top. I texture just the top of the shingles (not all faces/bottom), I then use the Area for this texture to takeoff shingles, sheathing, underlayment, etc.
You can also use the Area tool that comes with Estimator and simply add the faces to a collection, and use the total for your takeoff.
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