How to degree a cam

Hello. I am new to engine building. Why would one need to degree a cam on an engine that has manufacturer specific cam timing and crankshaft marks?

It's more about aftermarket camshafts that have different specs than stock ones.

It depends on the engine - some have marks on the various pulleys that need to be aligned, some will use differently coloured links on their cam' chain(s) or coloured marks on their cam belt that need to be aligned with marks on their sprockets or pulleys.

If it's a stock engine you can just use the manufacturers method, even many mild aftermarket camshafts will use the OEM method, and unless you feel the need, and have the experience to do so, the best option is usually to use that.

What, exactly, is the engine you're asking about?

Thank you for your insights. I think I am answered now. I am working on a motorcycle engine (Yamaha R1)