Skull hat

Hello i am very new to 3dcoat and digital sculpting in general. In my class we are tasked with making a monster due. im making a bug man and one thing i would like to add is spikes on certain bits. but im having a hard time just making a nice round spike. all the current curves i possess even the holo circles dont make nice sharp spikes im looking for. is there a way to just make nice sharp spikes in 3d coat?

Hello, I am a Student for game design and animation. Im currently learning 3d coat and working on a monster man.