In general , point and curve primitives are able to provide sharp corners and ridge features ; sphere primitives are able to achieve smoothing effects and provide semi - sharp features ; and cube primitives are able to handle sharp corners , sharp edges and flat faces with the corners , edges and faces of the cubes respectively 点和曲线编辑工具可以用来获取尖锐的或“脊”的编辑效果,球体编辑工具可以用来作为平滑工具或得到半尖锐的细节特征,立方体编辑工具可以用来获取尖角、尖锐的棱边和平坦的小面。