This post might be specific to IDA Pro, so bear that in mind.I'm currently trying to write a plugin for debugging specifically one executable. I know that a certain object in the executable's process exists at 0xAB40C0 (it always exists there). Can I simply write object* obj = (object*)0xAB40C0; and then access the various members of it? 
During debugging, is the process memory the same as the debugger's memory space?
ida;debugging;c
No, the debugger (in whose process context your plugin is running) and the debuggee are two separate processes.You would need to use ReadProcessMemory() (or its equivalent for your operating system) to read the debuggee's memory.